Showing papers on "Gene published in 1978"
TL;DR: High molecular weight DNA from cells containing only one copy of the HSV gene coding for tk was successfully used to transform L+K-cells to the tk+ phenotype, and the acquired phenotype was demonstrated to be donor-derived by analysis of the electrophoretic mobility of the tK activity.
1,188 citations
TL;DR: The determination of the total 5,224 base-pair DNA sequence of the virus SV40 has enabled us to locate precisely the known genes on the genome.
Abstract: The determination of the total 5,224 base-pair DNA sequence of the virus SV40 has enabled us to locate precisely the known genes on the genome. At least 15.2% of the genome is presumably not translated into polypeptides. Particular points of interest revealed by the complete sequence are the initiation of the early t and T antigens at the same position and the fact that the T antigen is coded by two non-contiguous regions of the genome; the T antigen mRNA is spliced in the coding region. In the late region the gene for the major protein VP1 overlaps those for proteins VP2 and VP3 over 122 nucleotides but is read in a different frame. The almost complete amino acid sequences of the two early proteins as well as those of the late proteins have been deduced from the nucleotide sequence. The mRNAs for the latter three proteins are presumably spliced out of a common primary RNA transcript. The use of degenerate codons is decidedly non-random, but is similar for the early and late regions. Codons of the type NUC, NCG and CGN are absent or very rare.
1,000 citations
TL;DR: Selected regions of cloned EcoRI fragments of the chicken ovalbumin gene have been sequenced, and a previously unreported interruption in the DNA sequences coding for the 5' nontranslated region of the messenger has been discovered.
Abstract: Selected regions of cloned EcoRI fragments of the chicken ovalbumin gene have been sequenced. The positions where the sequences coding for ovalbumin mRNA (ov-mRNA) are interrupted in the genome have been determined, and a previously unreported interruption in the DNA sequences coding for the 5' nontranslated region of the messenger has been discovered. Because directly repeated sequences are found at exon-intron boundaries, the nucleotide sequence alone cannot define unique excision-ligation points for the processing of a possible ov-mRNA precursor. However, the sequences in these boundary regions share common features; this leads to the proposal that there are, in fact, unique excision-ligation points common to all boundaries.
945 citations
TL;DR: The two independently isolated β-globin clones differ from each other by the presence of a Pst I restriction enzyme cleavage site within the large intervening sequence of the δ- globin gene of one of the clones, which suggests that the human DNA carried in the two clones was derived from two homologous chromosomes which were heterozygous for the PstI restriction enzyme recognition sequence.
850 citations
TL;DR: The nucleotide sequence of SV40 DNA was determined, and the sequence was correlated with known genes of the virus and with the structure of viral messenger RNA's.
Abstract: The nucleotide sequence of SV40 DNA was determined, and the sequence was correlated with known genes of the virus and with the structure of viral messenger RNA9s. There is a limited overlap of the coding regions for structural proteins and a complex pattern of leader sequences at the 59 end of late messenger RNA. The sequence of the early region is consistent with recent proposals that the large early polypeptide of SV40 is encoded in noncontinguous segments of DNA.
810 citations
TL;DR: The nucleotide sequence of the ampicillin resistance gene of pBR322, an Escherichia coli plasmid that encodes a penicillin beta-lactamase, is determined and the first 23 amino acids presumably form a signal for secretion.
Abstract: I have determined the nucleotide sequence of the ampicillin resistance gene of pBR322, an Escherichia coli plasmid that encodes a penicillin beta-lactamase. This gene codes for a protein of 286 amino acid residues. The first 23 amino acids presumably form a signal for secretion, because they do not appear in the mature enzyme, whose partial amino acid sequence has been determined independently.
772 citations
TL;DR: Restriction endonuclease mapping of the human globin genes revealed a genetic variation in a Hpa I recognition site about 5000 nucleotides from the 3' end of the beta-globin structural gene.
Abstract: Restriction endonuclease mapping of the human globin genes revealed a genetic variation in a Hpa I recognition site about 5000 nucleotides from the 39 end of the beta-globin structural gene. Instead of a normal 7.6-kilobase (kb) fragment which contains the beta-globin structural gene, 7.0-kb and 13.0-kb variants were detected. Both variants were found in people of African origin and were not detected in Asians or Caucasians. The 13.0-kb variant is frequently associated with the sickle hemoglobin mutation and may be useful for the prediction of the sickle cell gene in prenatal diagnosis. Polymorphism in a restriction enzyme site could be considered as a new class of genetic marker and may offer a new approach to linkage analysis and anthropological studies.
721 citations
TL;DR: Synthetic maps constructed for Europe and the Near East show clines in remarkable agreement with those expected on the basis of the spread of early farming in Europe, supporting the hypothesis that this spread was a demic spread rather than a cultural diffusion of farming technology.
Abstract: Multivarate techniques can be used to condense the information for a large number of loci and alleles into one or a few synthetic variables. The geographic distribution of synthetic variables can be plotted by the same technique used in mapping the gene frequency of a single allele. Synthetic maps were constructed for Europe and the Near East, with the use of principal components to condense the information of 38 independent alleles from ten loci. The first principal component summarizes close to 30% of the total information and shows gradients. Maps thus constructed show clines in remarkable agreement with those expected on the basis of the spread of early farming in Europe, thus supporting the hypothesis that this spread was a demic spread rather than a cultural diffusion of farming technology.
652 citations
TL;DR: Eukaryote DNA can be divided into genic DNA, which codes for proteins (or serves as recognition sites for proteins involved in transcription, replication and recombination), and nucleoskeletal DNA (S-DNA), which exists only because of its nucleoskeleton role in determining the nuclear volume.
Abstract: The 40,000-fold variation in eukaryote haploid DNA content is unrelated to organismic complexity or to the numbers of protein-coding genes. In eukaryote microorganisms, as well as in animals and plants, DNA content is strongly correlated with cell volume and nuclear volume, and with cell cycle length and minimum generation time. These correlations are simply explained by postulating that DNA has 2 major functions unrelated to its protein-coding capacity: (1) the control of cell volume by the number of replicon origins, and (2) the determination of nuclear volume by the overall bulk of the DNA: cell growth rates are determined by the cell volume and by the area of the nuclear envelope available for nucleocytoplasmic transport of RNA, which in turn depends on the nuclear volume and therefore on the DNA content. During evolution nuclear volume, and therefore DNA content, has to be adjusted to the cell volume to allow reasonable growth rates. The great diversity of cell volumes and growth rates, and therefore of DNA contents, among eukaryotes results from a varying balance in different species between r-selection, which favours small cells and rapid growth rates and therefore low DNA C-values, and K-selection which favours large cells and slow growth rates and therefore high DNA C-values. In multicellular organisms cell size needs to vary in different tissues: size differences between somatic cells result from polyteny, endopolyploidy, or the synthesis of nucleoskeletal RNA. Conflict between the need for large ova and small somatic cells explains why lampbrush chromosomes, nurse cells, chromatin diminution and chromosome elimination evolved. Similar evolutionary considerations clarify the nature of polygenes, the significance of the distribution of haploidy, diploidy and dikaryosis in life cycles and of double fertilization in angiosperms, and of heteroploidy despite DNA constancy in cultured cells, and other puzzles in eukaryote chromosome biology. Eukaryote DNA can be divided into genic DNA (G-DNA), which codes for proteins (or serves as recognition sites for proteins involved in transcription, replication and recombination), and nucleoskeletal DNA (S-DNA) which exists only because of its nucleoskeletal role in determining the nuclear volume (which it shares with G-DNA, and performs not only directly, but also indirectly by coding for nucleoskeletal RNA). Mechanistic and evolutionary implications of this are discussed.
646 citations
TL;DR: Correlation of the structure of two cytoplasmic spliced viral RNAs detected in CV-1 cells during the early phase of simian virus 40 (SV40) infection suggests that expression of the early SV40 genes is partially controlled at the level of splicing of RNAs.
Abstract: Biochemical methods are presented for determining the structure of spliced RNAs present in cells at low concentrations. Two cytoplasmic spliced viral RNAs were detected in CV-1 cells during the early phase of simian virus 40 (SV40) infection. One is 2200 nucleotides in length and is composed of two parts, 330 and 1900 nucleotides, mapping from ∼0.67 to ∼0.60 and from ∼0.54 to ∼0.14, respectively, on the standard viral map. The other is 2500 nucleotides long and also is composed of two parts, 630 and 1900 nucleotides mapping from ∼0.67 to ∼0.54 and from ∼0.54 to ∼0.14, respectively. Correlation of the structure of these mRNAs with the structure of the early SV40 proteins, small T antigen (17,000 daltons) and large T antigen (90,000 daltons), determined by others suggests that: (i) translation of the 2500-nucleotide mRNA yields small T antigen; (ii) translation of the 2200-nucleotide mRNA proceeds through the splice point in the RNA to produce large T antigen (and thus large T antigen is encoded in two separate regions of the viral genome); and (iii) the DNA sequences between ∼0.67 and ∼0.60 present in both mRNAs are translated in the same reading frame in both mRNAs to yield two separate gene products that have the same NH2-terminal sequence. Therefore, expression of the early SV40 genes is partially controlled at the level of splicing of RNAs.
625 citations
TL;DR: The structure of adenovirus 2 (Ad2) cytoplasmic RNAs produced during the early phase of infection is defined and it is suggested that, like the SV40 tumor antigens, the polypeptides encoded by these Ad2 mRNAs have an identical amino acid sequence at their N terminal ends, but have different C terminal sequences.
TL;DR: It is reported here that Tn5, a transposon coding for kanamycin resistance2, can insert into the chromosome of Rhizobium leguminosarum, the bacterium responsible for nodulation and nitrogen fixation in Pisum, Vicia, Lathyrus and Lens.
Abstract: TRANSPOSONS are discrete sequences of DNA that are incapable of self-replication and can insert into DNA replicons, such as chromosomes or plasmids, in the absence of the recA gene function1. Insertion can be random and where it occurs into the continuity of a gene leads to non-leaky polar mutations1. Some transposons carry drug resistance genes and thus insertions can be mapped as drug-resistance markers1. We report here that Tn5, a transposon coding for kanamycin resistance2, can insert into the chromosome of Rhizobium leguminosarum, the bacterium responsible for nodulation and nitrogen fixation in Pisum, Vicia, Lathyrus and Lens.
TL;DR: Analysis of 140 independently occurring spontaneous mutations in the lacI gene of Escherichia coli shows that the tandemly repeating sequence 5′-C-T-G-G
TL;DR: The sensitivity of in situ hybridization has been increased at least 10-fold by hybridizing in cDNA excess, by increasing the diffusion of the cDNA through the cells, by hybridization at optimum temperature, and by stabilizing hybrids during autoradiography.
Abstract: The sensitivity of in situ hybridization has been increased at least 10-fold by hybridizing in cDNA excess, by increasing the diffusion of the cDNA through the cells, by hybridizing at optimum temperature, and by stabilizing hybrids during autoradiography. Saturation of intracellular RNA with [3H]cDNA has been achieved. The assay is quantitative. In situ hybridization has been used to detect and quantitate visna virus RNA in infected cells. By using [3H]cDNA with specific activity of 2 X 10(8) dpm/micrograms and conditions that reduce background to negligible levels, 10--20 copies of viral RNA per cell can be detected and quantitated after 2 days of autoradiographic exposure.
TL;DR: The structural gene for the lac repressor of Escherichia coli, the lacI gene has been sequenced and the DNA sequence largely confirms but extends the previously reported protein sequence and allows a structural analysis of genetic phenomena.
Abstract: The structural gene for the lac repressor of Escherichia coli, the lacI gene has been sequenced. This 1,080 base pair region of the E. coli chromosome codes for the lac repressor protein of 360 amino acids. The DNA sequence largely confirms but extends the previously reported protein sequence and allows a structural analysis of genetic phenomena.
TL;DR: The nucleotide sequences of the germ line gene as well as a corresponding somatically mutated and rearranged gene coding for a mouse immunoglobulin lambdaI type light chain are determined and confirm the previously drawn conclusion that an active complete lambdaI gene arises by somatic recombination.
TL;DR: The sequence confirms that the variable region gene lies on the DNA separated from the constant region of a mouse immunoglobulin light chain, the VlambdaII gene, andHypervariable region codons appear in the germ-line sequence.
Abstract: We have determined the sequence of the DNA of a germ-line gene for the variable region of a mouse immunoglobulin light chain, the VlambdaII gene. The sequence confirms that the variable region gene lies on the DNA separated from the constant region. Hypervariable region codons appear in the germ-line sequence. A sequence for the hydrophobic leader, 19 amino acids that are cleaved from the amino terminus of the protein, appears near, but not continuous with, the light chain structural sequence: most of the leader sequence is separated from the rest of the gene by 93 bases of untranslated DNA.
TL;DR: The possible use of the genetic system of yeast mitochondria as a model for studies in gene organization, expression, recombina review and translation is focused on.
TL;DR: The entire nucleotide sequence of a cloned β-globin maj gene derived from the BALB/c mouse is determined, which establishes the fact that the gene is encoded in three discontinuous segments of DNA interrupted by two intervening sequences and precisely locates each.
TL;DR: The existence of a single active tk gene in tk+ transformants now facilitates an analysis of the sequence organization of tk- mutant cells and provides a useful model system for studies on the transfer of cellular genes.
TL;DR: Motile, but generally nonchemotactic mutants of Escherichia coli were examined for complementation and recombination with specialized lambdafla transducing phages, finding mutants defective in cheA, cheW, cheX, or cheY function swam smoothly, whereas cheB or cheZ mutants exhibited very high tumbling rates.
Abstract: Motile, but generally nonchemotactic (che) mutants of Escherichia coli were examined for complementation and recombination with specialized lambdafla transducing phages. The complex complementation behavior of these mutants found previously in F-prime tests could largely be accounted for by intragenic complementation and by polarity effects. Mutants of the "cheA" class defined two genes, cheA and cheW, which appeared to be contranscribed. Mutants of the "cheB" class defined four genes, cheX, cheB, cheY, and cheZ, which also constituted a transcriptional unit. Mutants defective in cheA, cheW, cheX, or cheY function swam smoothly, with little or no tumbling, whereas cheB or cheZ mutants exhibited very high tumbling rates. These functions are probably involved in initiating of controlling changes in flagellar rotation in response to chemotactic stimuli.
TL;DR: Gene amplification may underlie many such resistance phenomena and in some variants high resistance and gene copy number are stable in the absence of selection pressure, whereas in others they are unstable.
Abstract: Resistance of mouse cells to the folate analog, methotrexate, results from selection of increasingly resistant cells on progressive increases of methotrexate in the culture medium. High-level resistance is associated with high rates of synthesis of dihydrofolate reductase and correspondingly high numbers of reductase genes. In some variants high resistance and gene copy number are stable in the absence of selection pressure, whereas in others they are unstable. Analogies are made to antibiotic and insecticide resistance wherein selection of organisms with increased capacity to counteract the drug effect results in emergence of resistance. Gene amplification may underlie many such resistance phenomena.
TL;DR: Two hundred and thirty-five Nif- strains of Klebsiella pneumoniae were characterized by two-dimensional polyacrylamide gel electrophoresis, and nine nif-coded polypeptides were identified, and eight of these were assigned to specific nif genes.
Abstract: Two hundred and thirty-five Nif- strains of Klebsiella pneumoniae were characterized by two-dimensional polyacrylamide gel electrophoresis. Forty-two of these strains were tested further by in vitro acetylene reduction assays. By these techniques, nine nif-coded polypeptides were identified, and eight of these were assigned to specific nif genes. Nitrogenase component I required nifK and nifD, which coded for the beta and alpha subunits, and nifB, -E, and -N were required for the iron-molybdenum cofactor, which is a part of the active site of nitrogenase. nifH coded for the structural protein of component II, and nifM and nifS products seemed to be necessary for the synthesis of an active component II. There were two genes, nifF and nifJ, that were required for N2 fixation in vivo but not for N2 fixation in vitro. There were at least two cases (nifE and nifN, nifK and nifD) of two proteins that seemed to require each other for stability in vivo. Regulation of N2 fixation is apparently complex, and this is reflected by the assignment of regulatory functions to the gene products of nifA, nifL, nifK, nifD, nifH, and NIFJ. Images
TL;DR: Two dimensional polyacrylamide gel electrophoresis of Non-Idet P-40 extracts and of specific Ia immunoprecipitates from [35S]methionine- labeled mouse spleen lymphocytes has revealed that the cell surface expression of some Ia antigens appears to be controlled by two genes.
Abstract: Two dimensional polyacrylamide gel electrophoresis of Non-Idet P-40 extracts and of specific Ia immunoprecipitates from [35S]methionine-labeled mouse spleen lymphocytes has revealed that the cell surface expression of some Ia antigens appears to be controlled by two genes. One locus, which maps in the I-A subregion, is probably the structural gene for an Ia polypeptide chain. The second locus, which maps between the I-J and H-2D regions, controls whether this I-A encoded molecule (Ae) remains in the cytoplasm or is modified and expressed on the cell surface. Complementation between these two loci allowing surface expression of Ae can occur in the cis or trans chromosomal position. Both the I-A molecule and a polypeptide chain coded for by a locus in I-E are coprecipitated by anti-I-E antibodies, suggesting that these two chains are associated with each other as a multisubunit complex in the cell. Because the ability to complement I-A for Ae expression is a property only of those strains which synthesize an I-E-encoded protein, it is likely that the I-E product itself is regulating the expression of Ae. These observations suggest several mechanisms by which interaction between two I region loci can generate new cell surface molecules. As a result, they may have important implications for understanding the molecular basis of two gene control of immune responsiveness and immune suppression.
TL;DR: The development of a plasmid transformation system for Streptomyces which should allow the cloning of any DNA sequence into these organisms and which, potentially, provides a means of directly manipulating the pathways of antibiotic production.
Abstract: OVER 60% of known antibiotics1 are produced by Streptomyces species, including many substances with valuable clinical and other applications; they therefore have considerable medical, biological and commercial importance. Although the process of gene exchange mediated by conjugation within these actinomycetes is apparently widespread2, the transfer of genetic material between individuals by such sexual means is, by definition, predominantly restricted to members of the same species. Transfer of genes as free DNA (transformation) or by viral mediation (transduction) has been well documented in some microorganisms3–5, but the efficiency of these processes also falls dramatically with increasing divergence of the species involved, as the homology of their DNA sequences decreases. In any case, the occurrence of these processes in streptomycetes remains to be established. This situation has hitherto precluded the generation of new combinations of DNA sequences from diverse actinomycete species which could have profoundly beneficial effects on both the range of chemical structure and the quantity of antibiotics produced6. We report here the development of a plasmid transformation system for Streptomyces which should allow the cloning of any DNA sequence into these organisms and which, potentially, provides a means of directly manipulating the pathways of antibiotic production. The system involves the uptake of covalently closed circular (ccc) DNA by protoplasts in the presence of polyethylene glycol (PEG) and the visual detection of transformants, at high resolution, after regeneration of the protoplasts.
TL;DR: Family studies showed that this polymorphism of C4 did not segregate with HLA histocompatibility genes in a fashion governed by two codominant alleles at a single genetic locus, in agreement with the hypothesis that two different genetic loci control the electrophoretic patterns of C 4.
Abstract: An electrophoretic polymorphism of the fourth component of human complement (C4) is described. Three patterns of bands of C4 were observed in EDTA plasma from a panel of unrelated blood donors and family members by using the technique of immunofixation electrophoresis. These patterns consisted of four fast-moving anodal bands (F), four slow-moving cathodal bands (S), or a combination of both the F and S bands (FS). The C4 patterns of bands were observed in EDTA plasma and not in serum. Family studies showed that this polymorphism of C4 did not segregate with HLA histocompatibility genes in a fashion governed by two codominant alleles at a single genetic locus. The family data are in agreement with the hypothesis that two different genetic loci control the electrophoretic patterns of C4. One locus controls the presence (F) or absence (f0) of the four anodal (F) bands and the other controls the presence (S) or absence (s0) of the four cathodal (S) bands. The C4F and C4S loci are both closely linked to HLA-B.
Journal Article•
TL;DR: Mup-1 is known to be linked to the brown coat color locus on chromosome 4 in mice; thus Lps can now be assigned to chromosome 4, and the polysyndactyly (Ps) mutation is used further to localize Lps on chromosomes 4.
Abstract: The expression of a defective LPS response gene Lps and the major urinary protein (Mup-1) are concordantly inherited in backcross (C3H/HeJ x C57BL/6J)F1 x C3H/HeJ mice, indicating genetic linkage of these loci. Mup-1 is known to be linked to the brown coat color locus on chromosome 4 in mice; thus Lps can now be assigned to chromosome 4. A value of 0.06 +/- 0.02 has been estimated for the recombination frequency between Mup-1 and Lps. We have used the polysyndactyly (Ps) mutation further to localize Lps on chromosome 4. Lps is located between the Mup-1 and Ps loci.
TL;DR: It is shown that wild-type yeast contains such an enzymatic activity, and that this activity specifically removes the intervening sequences to produce mature-sized RNAs.