Showing papers on "Gene published in 1985"
TL;DR: A probe based on a tandem-repeat of the core sequence can detect many highly variable loci simultaneously and can provide an individual-specific DNA ‘fingerprint’ of general use in human genetic analysis.
Abstract: The human genome contains many dispersed tandem-repetitive 'minisatellite' regions detected via a shared 10-15-base pair 'core' sequence similar to the generalized recombination signal (chi) of Escherichia coli. Many minisatellites are highly polymorphic due to allelic variation in repeat copy number in the minisatellite. A probe based on a tandem-repeat of the core sequence can detect many highly variable loci simultaneously and can provide an individual-specific DNA 'fingerprint' of general use in human genetic analysis.
3,552 citations
TL;DR: A protocol is described for rapidly generating large blocks of 16S rRNA sequence data without isolation of the 16 S rRNA or cloning of its gene, and its phylogenetic usefulness is evaluated by examination of several 17S rRNAs whose gene sequences are known.
Abstract: Although the applicability of small subunit ribosomal RNA (16S rRNA) sequences for bacterial classification is now well accepted, the general use of these molecules has been hindered by the technical difficulty of obtaining their sequences. A protocol is described for rapidly generating large blocks of 16S rRNA sequence data without isolation of the 16S rRNA or cloning of its gene. The 16S rRNA in bulk cellular RNA preparations is selectively targeted for dideoxynucleotide-terminated sequencing by using reverse transcriptase and synthetic oligodeoxynucleotide primers complementary to universally conserved 16S rRNA sequences. Three particularly useful priming sites, which provide access to the three major 16S rRNA structural domains, routinely yield 800-1000 nucleotides of 16S rRNA sequence. The method is evaluated with respect to accuracy, sensitivity to modified nucleotides in the template RNA, and phylogenetic usefulness, by examination of several 16S rRNAs whose gene sequences are known. The relative simplicity of this approach should facilitate a rapid expansion of the 16S rRNA sequence collection available for phylogenetic analyses.
3,006 citations
Book•
01 Jan 1985
TL;DR: The construction and characterization of vaccinia virus recombinants expressing foreign genes Bovine papilloma virus DNA: A eukaryotic cloning vector is studied.
Abstract: Bacillus cloning methods Gene cloning in streptomyces Cloning in yeast Genetic Engineering of plants P element mediated germ line transformation of drosophila High efficiency gene transfer into mammalian cells The construction and characterization of vaccinia virus recombinants expressing foreign genes Bovine papilloma virus DNA: A eukaryotic cloning vector
2,266 citations
TL;DR: Chromosome 18-specific DNA probes for the areas flanking the breakpoints also detected RNA transcripts 6 kilobases in length in various cell types, and the gene coding for these transcript seems to be interrupted in most cases of follicular lymphomas carrying the t(14;18) chromosomal translocation.
Abstract: Recombinant DNA probes were cloned for the areas flanking the breakpoint on chromosome 18 in cells from a patient with acute lymphocytic leukemia of the B-cell type; cells of this line carry the t(14;18) chromosomal translocation. Two of the probes detected DNA rearrangements in approximately 60 percent of the cases of follicular lymphoma screened. In follicular lymphoma, most of the breakpoints in band q21 of chromosome 18 were clustered within a short stretch of DNA, approximately 2.1 kilobases in length. Chromosome 18-specific DNA probes for the areas flanking the breakpoints also detected RNA transcripts 6 kilobases in length in various cell types. The gene coding for these transcript (the bcl-2 gene) seems to be interrupted in most cases of follicular lymphomas carrying the t(14;18) chromosomal translocation.
1,854 citations
TL;DR: Information is provided on how to identify the Steroid Receptors, Receptor Binding Sites, and other mechanisms that aid in the identification of the receptors and their locations in the genome.
Abstract: PERSPECTIVES AND SUMMARY . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 210 ORIGINS OF CONSERVED GENE REGULATORS . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . 211 Steroids . . . . .. . . . . . . . . . . . . . . . . . . . .. . . .. . . . . . . . . . . . .. . . . . .. . . . . . . . . . . . . . .... . . . . . . .. . . . . . . . .. . . . . . . .. . 211 Steroid Receptors .... " . . . . . . . . . . . . . . . . . . . . . " . . . . . . . . . . . . . . . . . . . . . . . . "" . . . . . . . . . . . . . . . . . . . . . . " 211 FUNCTIONAL ASPECTS OF RECEPTOR STRUCTURE" . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 213 Activation and Intracellular Localization ... . ". . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 213 Steroid Binding .. ...... , . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . " . . . . . . . . . . . . . . . . . . , 214 Nonspecific DNA Binding . .. . ..... ....... . ....... " . . . . . . . . .. . . . . . . . . . . . . . . . . " 215 Functional Heterogeneity 216 SELECTIVE RECEPTOR:DNA INTERACTIONS ... . . .... .. .... . .... . 21 7 Receptor Binding at Genomic Sites of Action . " . . . . . . . " 218 Detection of Specific DNA Binding Sites """""",,, , , """""'" . . . . . . . . . . . . . . . . . . . . . . . 21 8 DNA Sequences Bound by Steroid Receptors .. . ......... . ..... . ..... . ..... . ... , 221 LOCALIZATION OF STEROID RESPONSE ELEMENTS (REs) . .... " . . . . . . . . . 222 Deletion Mapping .. . ..... ......... . ....... . " . . . . . . . . . . . . . . . . . . . . . ""." . . .... . . . 223 RE-Promoter Fusions .... ......... . " . . . . . . . . . . . . . . . . . ". . . . . . . . . . . . . . . . . . 223 In Vitro Mutagenesis" ...... . ........ ......... .. " . . . . . . . . . . . . . . . . . "" . . . . . . " . . . . . . . . . . . . . . . . " 224 TRANSCRIPTIONAL ENHANCEMENT BY RECEPTOR:RE COMPLEXES " " "'" ' ' 224 Glucocorticoid-Dependent Enhancement 225 Detection and Characterization of Enhancers. . .. . . . . . . .... . . .... . . . . . . .. . . . . . . .... . . ... . . . . 225 EFFECTS OF RECEPTOR BINDING ON GENOME STRUCTURE ... " . . ". . . . . . . . . . . . . . 227 Cytological and Nuclease Probes .. . . """""" . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . " . . . . . . . . . 227 Chromosomal Protein Alterations 229 DNA-Structure Alterations 230 New Experimental Approaches . . . . . ... """ . . ,, .. " . . . . ,,". . . . . . . . . . . . . . . . . . . . . . . . . 232 HIGHER-ORDER CONTROL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . .. 233 Gene Networks ..... ...... ........ ....... . " . . . . . . . . , . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ". . . . . . . . . 234 Multifactor Regulation ...... ... ,. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 235
1,837 citations
TL;DR: Comparison of these two cDNA sequences with those of the chicken, Drosophila and yeast genes allows the analysis of the evolution of the GAPDH genes in detail.
Abstract: Full length cDNAs encoding the glycolytic enzyme glyceraldehyde-3-phosphate dehydrogenase (GAPDH) from rat and man have been isolated and sequenced. Many GAPDH gene-related sequences have been found in both genomes based on genomic blot hybridization analysis. Only one functional gene product is known. Results from genomic library screenings suggest that there are 300-400 copies of these sequences in the rat genome and approximately 100 in the human genome. Some of these related sequences have been shown to be processed pseudogenes. We have isolated several rat cDNA clones corresponding to these pseudogenes indicating that some pseudogenes are transcribed. Rat and human cDNAs are 89% homologous in the coding region, and 76% homologous in the first 100 base pairs of the 3'-noncoding region. Comparison of these two cDNA sequences with those of the chicken, Drosophila and yeast genes allows the analysis of the evolution of the GAPDH genes in detail.
1,773 citations
TL;DR: Two distinct but distantly related complementary DNAs encoding proteins sharing human interleukin-1 (IL-1) activity (termed IL-lα and IL-1β), were isolated from a macrophage cDNA library.
Abstract: Two distinct but distantly related complementary DNAs encoding proteins sharing human interleukin-1 (IL-1) activity (termed IL-1 alpha and IL-1 beta), were isolated from a macrophage cDNA library. The primary translation products of the genes are 271 and 269 amino acids long, although expression in Escherichia coli of the carboxy-terminal 159 and 153 amino acids produces IL-1 biological activity.
1,630 citations
TL;DR: Evidence is summarized that supports the hypothesis that A and T nucleotides are favored at all locations in the D. yakuba mtDNA molecule where these nucleotide are compatible with function.
Abstract: The sequence of the 16,019 nucleotide-pair mitochondrial DNA (mtDNA) molecule ofDrosophila yakuba is presented. This molecule contains the genes for two rRNAs, 22 tRNAs, six identified proteins [cytochrome b, cytochrome c oxidase subunits I, II, and III (COI-III), and ATPase subunits 6 and 8] and seven presumptive proteins (URF1-6 and URF4L). Replication originates within a region of 1077 nucleotides that is 92.8% A+T and lacks any open reading frame larger than 123 nucleotides. An equivalent to the sequence found in all mammalian mtDNAs that is associated with initiation of second-strand DNA synthesis is not present inD. yakuba mtDNA. Introns are absent fromD. yakuba mitochondrial genes and there are few (0–31) intergenic nucleotides. The genes found inD. yakuba and mammalian mtDNAs are the same, but there are differences in their arrangement and in the relative proportions of the complementary strands of the molecule that serve as templates for transcription. Although theD. yakuba small and large mitochondrial rRNA genes are exceptionally low in G and C and are shorter than any other metazoan rRNA genes reported, they can be folded into secondary structures remarkably similar to the secondary structures proposed for mammalian mitochondrial rRNAs.D. yakuba mitochondrial tRNA genes, like their mammalian counterparts, are more variable in sequence than nonorganelle tRNAs. In mitochrondrial protein genes ATG, ATT, ATA, and in one case (COI) ATAA appear to be used as translation initiation codons. The only termination codon found in these genes is TAA. In theD. yakuba mitochondrial genetic code, AGA, ATA, and TGA specify serine, isoleucine, and tryptophan, respectively. Fifty-nine types of sense codon are used in theD. yakuba mitochondrial protein genes, but 93.8% of all codons end in A or T. Codon-anticodon interactions may include both G-A and C-A pairing in the wobble position. Evidence is summarized that supports the hypothesis that A and T nucleotides are favored at all locations in theD. yakuba mtDNA molecule where these nucleotides are compatible with function.
1,436 citations
TL;DR: It is shown that circular DNAs containing oriP, the EBNA-1 gene and a selectable marker replicate autonomously in cells derived from at at least four developmental lineages and from at least three species.
Abstract: Epstein-Barr virus (EBV) infects human B lymphocytes, transforming the infected cells into dividing blasts that can proliferate indefinitely. The viral genome of 172 kilobase pairs (kbp) is a plasmid in most transformed cells. We have identified a region of EBV DNA, termed oriP (nucleotides 7,333-9,109 of strain B95-8), which acts in cis to permit linked DNAs to replicate as plasmids in cells containing EBV DNA. We have postulated the existence of a trans-acting gene allowing oriP function. Here we report that this gene lies in a 2.6-kbp region of the viral genome (nucleotides 107, 567-110, 176) which encodes the EBNA-1 antigen. We show that circular DNAs containing oriP, the EBNA-1 gene and a selectable marker replicate autonomously in cells derived from at least four developmental lineages and from at least three species. We also find that the one-third of the EBNA-1 gene repetitive in sequence is not essential for the trans-acting function that EBNA-1 gives oriP.
1,346 citations
TL;DR: The HCMV enhancer, which seems to have little cell type or species preference, is severalfold more active than the SV40 enhancers, a property that makes it a useful component of eukaryotic expression vectors.
1,336 citations
TL;DR: DNA repair was measured in the dihydrofolate reductase gene in Chinese hamster ovary cells by quantitating pyrimidine dimers with a specific UV-endonuclease, suggesting preferential repair of vital sequences facilitates UV-resistance of these cells despite low overall repair levels.
TL;DR: The human erythropoietin gene has been isolated from a genomic phage library by using mixed 20-mer and 17-mer oligonucleotide probes and encodes a 27-amino acid signal peptide and a 166-AMino acid mature protein with a calculated Mr of 18,399.
Abstract: The human erythropoietin gene has been isolated from a genomic phage library by using mixed 20-mer and 17-mer oligonucleotide probes. The entire coding region of the gene is contained in a 5.4-kilobase HindIII-BamHI fragment. The gene contains four intervening sequences (1562 base pairs) and five exons (582 base pairs). It encodes a 27-amino acid signal peptide and a 166-amino acid mature protein with a calculated Mr of 18,399. The erythropoietin gene, when introduced into Chinese hamster ovary cells, produces erythropoietin that is biologically active in vitro and in vivo.
TL;DR: The overall efficiency of microinjection of foreign DNA into fertilized mammalian eggs depends on the choice of mouse strains; for example, generating transgenic mice that express foreign growth hormone genes is about eight times easier with C57/BL6 X SJL hybrid mice than with inbred C57-BL6 mice.
Abstract: Microinjection of foreign DNA into fertilized mammalian eggs is a convenient means of introducing genes into the germ line. Some of the more important parameters that influence successful integration of foreign DNA into mouse chromosomes are described. The effects of DNA concentration, size, and form (supercoiled vs. linear with a variety of different ends) are considered as well as the site of injection (male pronucleus, female pronucleus, or cytoplasm) and buffer composition. The optimal conditions for integration entail injection of a few hundred linear molecules into the male pronucleus of fertilized one-cell eggs. Under these conditions about 25% of the mice that develop inherit one or more copies of the microinjected DNA. The overall efficiency also depends on the choice of mouse strains; for example, generating transgenic mice that express foreign growth hormone genes is about eight times easier with C57/BL6 X SJL hybrid mice than with inbred C57/BL6 mice.
TL;DR: A new member of the tyrosine kinase proto-oncogene family has been identified on the basis of its amplification in a human mammary carcinoma.
Abstract: The cellular gene encoding the receptor for epidermal growth factor (EGF) has considerable homology to the oncogene of avian erythroblastosis virus. In a human mammary carcinoma, a DNA sequence was identified that is related to v-erbB but amplified in a manner that appeared to distinguish it from the gene for the EGF receptor. Molecular cloning of this DNA segment and nucleotide sequence analysis revealed the presence of two putative exons in a DNA segment whose predicted amino acid sequence was closely related to, but different from, the corresponding sequence of the erbB/EGF receptor. Moreover, this DNA segment identified a 5-kilobase transcript distinct from the transcripts of the EGF receptor gene. Thus, a new member of the tyrosine kinase proto-oncogene family has been identified on the basis of its amplification in a human mammary carcinoma.
TL;DR: A ‘rescuable’ plasmid containing globin gene sequences allowing recombination with homologous chromosomal sequences has enabled us to produce, score and clone mammalian cells with the plasmids integrated into the human β-globin locus.
Abstract: A 'rescuable' plasmid containing globin gene sequences allowing recombination with homologous chromosomal sequences has enabled us to produce, score and clone mammalian cells with the plasmid integrated into the human beta-globin locus. The planned modification was achieved in about one per thousand transformed cells whether or not the target gene was expressed.
TL;DR: Integration of the fusion gene in all three species and expression of the gene in transgenic rabbits and pigs are reported here.
Abstract: Direct microinjection has been used to introduce foreign DNA into a number of terminally differentiated cell types as well as embryos of several species including sea urchin, Candida elegans, Xenopus, Drosophila and mice. Various genes have been successfully introduced into mice including constructs consisting of the mouse metallothionein-I (MT) promoter/regulator region fused to either the rat or human growth hormone (hGH) structural genes. Transgenic mice harbouring such genes commonly exhibit high, metal-inducible levels of the fusion messenger RNA in several organs, substantial quantities of the foreign growth hormone in serum and enhanced growth. In addition, the gene is stably incorporated into the germ line, making the phenotype heritable. Because of the scientific importance and potential economic value of transgenic livestock containing foreign genes, we initiated studies on large animals by microinjecting the fusion gene, MT-hGH, into the pronuclei or nuclei of eggs from superovulated rabbits, sheep and pigs. We report here integration of the gene in all three species and expression of the gene in transgenic rabbits and pigs.
TL;DR: The implication of the results for the mechanisms of DNA evolution and that of the relative likelihood of codon interchanges in parsimonious phylogenetic reconstruction are discussed.
Abstract: A new method is proposed for estimating the number of synonymous and nonsynonymous nucleotide substitutions between homologous genes. In this method, a nucleotide site is classified as nondegenerate, twofold degenerate, or fourfold degenerate, depending on how often nucleotide substitutions will result in amino acid replacement; nucleotide changes are classified as either transitional or transversional, and changes between codons are assumed to occur with different probabilities, which are determined by their relative frequencies among more than 3,000 changes in mammalian genes. The method is applied to a large number of mammalian genes. The rate of nonsynonymous substitution is extremely variable among genes; it ranges from 0.004 X 10(-9) (histone H4) to 2.80 X 10(-9) (interferon gamma), with a mean of 0.88 X 10(-9) substitutions per nonsynonymous site per year. The rate of synonymous substitution is also variable among genes; the highest rate is three to four times higher than the lowest one, with a mean of 4.7 X 10(-9) substitutions per synonymous site per year. The rate of nucleotide substitution is lowest at nondegenerate sites (the average being 0.94 X 10(-9), intermediate at twofold degenerate sites (2.26 X 10(-9)). and highest at fourfold degenerate sites (4.2 X 10(-9)). The implication of our results for the mechanisms of DNA evolution and that of the relative likelihood of codon interchanges in parsimonious phylogenetic reconstruction are discussed.
Patent•
11 Feb 1985
TL;DR: Products of the invention include plants, plant tissues and seeds which exhibit resistance to such herbicides resulting from expression of genes encoding herbicide resistant acetohydroxyacid synthase enzyme.
Abstract: This invention is directed to the production of plants, plant tissues and seeds which are resistant to inhibition by an herbicide which normally inhibits the growth and development of those plants, plant tissues and plant seeds. In particular this invention is directed to altered acetohydroxyacid synthase enzymes which are resistant to inhibition by herbicides which normally inhibit the activity of the synthase before such alteration. This invention further relates to genes encoding such enzymes, and to processes for utilizing these novel genes and enzymes. Further products of the invention include plants, plant tissues and seeds which exhibit resistance to such herbicides resulting from expression of genes encoding herbicide resistant acetohydroxyacid synthase enzyme.
TL;DR: The sequence of the entire RNA genome of the type flavivirus, yellow fever virus, has been obtained and implies that mature viral proteins are produced by posttranslational cleavage of a polyprotein precursor and has implications for flaviv virus RNA replication and for the evolutionary relation of this virus family to other RNA viruses.
Abstract: The sequence of the entire RNA genome of the type flavivirus, yellow fever virus, has been obtained. Inspection of this sequence reveals a single long open reading frame of 10,233 nucleotides, which could encode a polypeptide of 3411 amino acids. The structural proteins are found within the amino-terminal 780 residues of this polyprotein; the remainder of the open reading frame consists of nonstructural viral polypeptides. This genome organization implies that mature viral proteins are produced by posttranslational cleavage of a polyprotein precursor and has implications for flavivirus RNA replication and for the evolutionary relation of this virus family to other RNA viruses.
TL;DR: The molecular cloning and characterization of a gene regulated by rIFN-γ in U937 cells as well as in human mononuclear cells, fibroblasts and endothelial cells is reported here and may be a member of a family of proteins involved in the inflammatory process.
Abstract: Interferons are a family of proteins first identified by their ability to induce cellular resistance to infection by many viruses. In addition to the antiviral properties it shares with the α- and β-interferons, γ-interferon (IFN-γ), a lymphokine secreted by activated T cells, activates macrophages, stimulates B cells, increases fibroblast and endothelial cell resistance to many non-viral intracellular parasites and modulates cell-surface proteins central to immune cell regulation1–13. To identify molecules involved in the IFN-γ response and characterize their modulation, we have isolated genes that are induced following recombinant IFN-γ treatment of U937 cells, a histiocytic lymphoma cell line with monocytic characteristics14,15. We report here the molecular cloning and characterization of a gene regulated by rIFN-γ in U937 cells as well as in human mononuclear cells, fibroblasts and endothelial cells. Messenger RNA from this gene is induced within 30 min of rIFN-γ treatment and demonstrates maximal (>30-fold) accumulation within 5 h. Increased transcription is partly responsible for this accumulation. This gene encodes a protein of relative molecular mass (Mr) 12,378 which has significant amino-acid homology to platelet factor-4 and β-thromboglobulin, two chemo-tatic proteins released by platelets on degranulation. This IFN-γ-inducible protein may be a member of a family of proteins involved in the inflammatory process.
TL;DR: This approach has revealed that the distribution of genes, integrated viral sequences, and interspersed repeats is highly nonuniform in the genome, and that the base composition and ratio of CpG to GpC in both coding and noncoding sequences, as well as codon usage, mainly depend on the GC content of the isochores harboring the sequences.
Abstract: Most of the nuclear genome of warm-blooded vertebrates is a mosaic of very long (much greater than 200 kilobases) DNA segments, the isochores; these isochores are fairly homogeneous in base composition and belong to a small number of major classes distinguished by differences in guanine-cytosine (GC) content. The families of DNA molecules derived from such classes can be separated and used to study the genome distribution of any sequence which can be probed. This approach has revealed (i) that the distribution of genes, integrated viral sequences, and interspersed repeats is highly nonuniform in the genome, and (ii) that the base composition and ratio of CpG to GpC in both coding and noncoding sequences, as well as codon usage, mainly depend on the GC content of the isochores harboring the sequences. The compositional compartmentalization of the genome of warm-blooded vertebrates is discussed with respect to its evolutionary origin, its causes, and its effects on chromosome structure and function.
TL;DR: Human T-lymphotropic virus type III (HTLV-III) encodes a trans-acting factor that activates the expression of genes linked to the HTLV- III long terminal repeat by functional mapping of complementary DNA transcripts of viral messenger RNA's.
Abstract: Human T-lymphotropic virus type III (HTLV-III) encodes a trans-acting factor that activates the expression of genes linked to the HTLV-III long terminal repeat. By functional mapping of complementary DNA transcripts of viral messenger RNA's the major functional domain of the gene encoding this factor was localized to a region immediately before the env gene of the virus, a region previously thought to be noncoding. This newly identified gene consists of three exons, and its transcription into messenger RNA involves two splicing events bringing together sequences from the 5' part (287 base pairs), middle (268 base pairs), and 3'part (1258 base pairs) of the HTLV-III genome. A similar messenger RNA with a truncated second exon (70 base pairs) does not encode a trans-acting function. It is proposed that this second messenger RNA is the transcript of a gene (3'-orf) located after the env gene. Messenger RNA's were also identified for the env and gag-pol genes of HTLV-III.
TL;DR: The lack of accumulated silent nucleotide substitutions leads us to propose that there may be additional information in the nucleotide sequence of the hsp70 gene or the corresponding mRNA that precludes the maximum divergence allowed in the silent codon positions.
Abstract: We have determined the nucleotide sequence of the human hsp70 gene and 5' flanking region. The hsp70 gene is transcribed as an uninterrupted primary transcript of 2440 nucleotides composed of a 5' noncoding leader sequence of 212 nucleotides, a 3' noncoding region of 242 nucleotides, and a continuous open reading frame of 1986 nucleotides that encodes a protein with predicted molecular mass of 69,800 daltons. Upstream of the 5' terminus are the canonical TATAAA box, the sequence ATTGG that corresponds in the inverted orientation to the CCAAT motif, and the dyad sequence CTGGAAT/ATTCCCG that shares homology in 12 of 14 positions with the consensus transcription regulatory sequence common to Drosophila heat shock genes. Comparison of the predicted amino acid sequences of human hsp70 with the published sequences of Drosophila hsp70 and Escherichia coli dnaK reveals that human hsp70 is 73% identical to Drosophila hsp70 and 47% identical to E. coli dnaK. Surprisingly, the nucleotide sequences of the human and Drosophila genes are 72% identical and human and E. coli genes are 50% identical, which is more highly conserved than necessary given the degeneracy of the genetic code. The lack of accumulated silent nucleotide substitutions leads us to propose that there may be additional information in the nucleotide sequence of the hsp70 gene or the corresponding mRNA that precludes the maximum divergence allowed in the silent codon positions.
TL;DR: Southern blot analysis of hamster, mouse and human DNA using this cDNA as a probe showed that P-glycoprotein is conserved and is probably encoded by a gene family, and that members of this putative family are amplified in multidrug-resistant cells.
Abstract: The multidrug-resistance phenotype expressed in mammalian cell lines is complex. Cells selected with a single agent can acquire cross-resistance to a remarkably wide range of compounds which have no obvious structural or functional similarities. The basis for cross-resistance seems to be a decreased net cellular accumulation of the drug involved, and has been attributed to alterations in the plasma membrane. An over-expressed plasma membrane glycoprotein of relative molecular mass (Mr) 170,000 (P-glycoprotein) is consistently found in different multidrug-resistant human and animal cell lines, and in transplantable tumours. Consequently, it has been postulated that P-glycoprotein directly or indirectly mediates multidrug resistance. Here we report the cloning of a complementary DNA encoding P-glycoprotein. Southern blot analysis of hamster, mouse and human DNA using this cDNA as a probe showed that P-glycoprotein is conserved and is probably encoded by a gene family, and that members of this putative family are amplified in multidrug-resistant cells.
TL;DR: Results show that the expression of genes in the nuclei of differentiated cells is remarkably plastic and susceptible to modulation by the cytoplasm, and the isolation of the genes encoding the tissue-specific trans-acting regulators responsible for muscle gene activation should now be possible.
Abstract: Heterokaryons provide a model system in which to examine how tissue-specific phenotypes arise and are maintained. When muscle cells are fused with nonmuscle cells, muscle gene expression is activated in the nonmuscle cell type. Gene expression was studied either at a single cell level with monoclonal antibodies or in mass cultures at a biochemical and molecular level. In all of the nonmuscle cell types tested, including representatives of different embryonic lineages, phenotypes, and developmental stages, muscle gene expression was induced. Differences among cell types in the kinetics, frequency, and gene dosage requirements for gene expression provide clues to the underlying regulatory mechanisms. These results show that the expression of genes in the nuclei of differentiated cells is remarkably plastic and susceptible to modulation by the cytoplasm. The isolation of the genes encoding the tissue-specific trans-acting regulators responsible for muscle gene activation should now be possible.
TL;DR: The LDL receptor appears to be a mosaic protein built up of exons shared with different proteins, and it therefore belongs to several supergene families.
Abstract: The multifunctional nature of coated pit receptors predicts that these proteins will contain multiple domains. To establish the genetic basis for these domains (LDL) receptor. This gene is more than 45 kilobases in length and contains 18 exons, most of which correlate with functional domains previously defined at the protein level. Thirteen of the 18 exons encode protein sequences that are homologous to sequences in other proteins: five of these exons encode a sequence similar to one in the C9 component of complement; three exons encode a sequence similar to a repeat sequence in the precursor for epidermal growth factor (EGF) and in three proteins of the blood clotting system (factor IX, factor X, and protein C); and five other exons encode nonrepeated sequences that are shared only with the EGF precursor. The LDL receptor appears to be a mosaic protein built up of exons shared with different proteins, and it therefore belongs to several supergene families.
TL;DR: The 9,213-nucleotide structure of the AIDS/ lymphadenopathy virus has been determined from molecular clones representing the integrated provirus and viral RNA and the sequence reveals that the virus is highly polymorphic and lacks significant nucleotide homology with type C retroviruses characterized previously.
Abstract: The 9,213-nucleotide structure of the AIDS/lymphadenopathy virus has been determined from molecular clones representing the integrated provirus and viral RNA. The sequence reveals that the virus is highly polymorphic and lacks significant nucleotide homology with type C retroviruses characterized previously. Together with an analysis of the two major viral subgenomic RNAs, these studies establish the coding frames for the gag, pol and env genes and predict the expression of a novel gene at the 3' end of the genome unrelated to the X genes of HTLV-1 and -II.
TL;DR: The study of fusion genes showed that in addition to the 5' activating element, transient accumulation of c-fosH RNA following serum stimulation requires sequences at the 3' end of the c- fosH gene.
TL;DR: A novel transforming gene was detected by transfection of NIH 3T3 cells with human lymphoma DNA and appeared to be activated by recombination between two unlinked human DNA segments, possibly by cointegration during transfections.
TL;DR: The nucleotide sequence of molecular clones of DNA from a retrovirus, ARV-2, associated with the acquired immune deficiency syndrome (AIDS), was determined and the cloned gag and env genes of ARv-2 were shown to express viral proteins.
Abstract: The nucleotide sequence of molecular clones of DNA from a retrovirus, ARV-2, associated with the acquired immune deficiency syndrome (AIDS) was determined. Proviral DNA of ARV-2 (9737 base pairs) has long terminal repeat structures (636 base pairs) and long open reading frames encoding gag (506 codons), pol (1003 codons), and env (863 codons) genes. Two additional open reading frames were identified. Significant amino acid homology with several other retroviruses was noted in the predicted product of gag and pol, but ARV-2 was as closely related to murine and avian retroviruses as it was to human T-cell leukemia viruses (HTLV-I and HTLV-II). By means of an SV-40 vector in transfected simian cells, the cloned gag and env genes of ARV-2 were shown to express viral proteins.