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Showing papers on "genomic DNA published in 1981"


Journal ArticleDOI
TL;DR: Friend leukemia cells resistant to cadmium toxicity were selected and revealed that the resistant cells are nearly tetraploid and contain, on the average, three very small chromosomes that are absent from non-resistant Friend cells.
Abstract: Friend leukemia cells resistant to cadmium toxicity were selected. More than 70% of total cysteine incorporation in these cells was into the metal-binding protein, metallothionein. We used cDNA and genomic DNA clones containing the metallothionein-I gene to measure the concentration of its mRNA, the rate of gene transcription, and the number of genes. On a per cell basis, optimally induced, cadmium-resistant cells have a 14-fold more metallothionein-I mRNA, a 6-fold higher rate of metallothionein-I gene transcription, and 6-fold more metallothionein-I genes than do nonresistant cells. Metaphase spreads revealed that the resistant cells are nearly tetraploid and contain, on the average, three very small chromosomes that are absent from non-resistant Friend cells.

274 citations


Journal ArticleDOI
TL;DR: DNA blotting analysis confirmed that the isolated segments of yeast DNA are colinear with yeast genomic DNA and that there are two nontandemly repeated enolase genes per haploid yeast genome.

255 citations


Journal ArticleDOI
01 Nov 1981-Cell
TL;DR: A model of amplification in which additional rounds of replication are specifically initiated within the central gene-containing regions, followed by bidirectional replication in the absence of discrete termination sites is suggested.

232 citations


Journal ArticleDOI
17 Dec 1981-Nature
TL;DR: Structural comparisons of germ-line and rearranged D segments suggest that D segments may recombine with each other, and seems to have been formed by the tandem amplification of large and still well conserved segments of genomic DNA.
Abstract: A family of germ-line immunoglobulin D-region genes has been cloned and mapped at regular intervals along a 33-kilobase length of human chromosomal DNA. Each member of the family varies slightly in sequence, but precisely conserves the recombinational signals and spacing that flank each gene. This region seems to have been formed by the tandem amplification of large and still well conserved segments of genomic DNA. Further, structural comparisons of germ-line and rearranged D segments suggest that D segments may recombine with each other.

197 citations


Journal ArticleDOI
15 May 1981-Science
TL;DR: The gene for prolactin has been located on chromosome 6 in humans in a different location from those of the genes for the related hormones chorionic somatomammotropin and growth hormone, and in somatic cell hybrids of human and mouse cells the 7.4-, 3.6-, and 3.3-kilobase mouse fragments were always present.
Abstract: The gene for prolactin has been located on chromosome 6 in humans. DNA fragments of 4.8 and 4.0 kilobases containing prolactin gene sequences were identified in human genomic DNA, whereas DNA fragments of 7.4, 3.6, and 3.3 kilobases containing prolactin gene sequences were found in mouse cells. In somatic cell hybrids of human and mouse cells the 7.4-, 3.6-, and 3.3-kilobase mouse fragments were always present, whereas the 4.8- and 4.0-kilobase human fragments were only present when human chromosome 6 was also present. We conclude that the prolactin gene resides on chromosome 6, a different location from those of the genes for the related hormones chorionic somatomammotropin and growth hormone.

165 citations


Journal ArticleDOI
TL;DR: The data suggest that an early replicon can be isolated from this region, and that this entire, normally unique, genomic segment can be cloned and mapped with respect to origins of DNA synthesis and promoters for transcription, as well as other genetic features of interest.
Abstract: For the eventual purpose of isolating and studying a single animal cell replicon, we have developed a methotrexate-resistant Chinese hamster ovary cell line that has amplified an early-replicating DNA sequence approximately 500 times; this sequence includes the gene coding for dihydrofolate reductase (DHFR; tetrahydrofolate dehydrogenase; 5,6,7,8-tetrahydrofolate:NADP+ oxidoreductase, EC 1.5.1.3). DHFR composes 30% of the cytoplasmic protein in this cell line, and DHFR mRNA represents 25% of the message translatable in vitro. After digestion of genomic DNA from resistant cells with restriction enzymes, a unique set of highly repetitive restriction fragments can be visualized on agarose gels by ethidium bromide staining. These bands are not present in digests of parental DNA. We estimate the total length of the unit repeated sequence to be 135 +/- 15 kilobase pairs. Regardless of the restriction enzyme utilized, a subset of these repetitive fragments hybridizes to radioactive DHFR cDNA. The homogeneously staining regions on mitotic chromosomes in which these amplified sequences are located are shown to be early-replicating, as are the highly repeated restriction fragments themselves. These data suggest that an early replicon can be isolated from this region, and that this entire, normally unique, genomic segment can be cloned and mapped with respect to origins of DNA synthesis and promoters for transcription, as well as other genetic features of interest.

146 citations


Journal ArticleDOI
01 Jan 1981-Nature
TL;DR: A plant gene coding for the major storage protein of the French bean was isolated from a genomic library constructed in the phage vector Charon 24A and revealed the presence of three intervening sequences.
Abstract: A plant gene coding for the major storage protein (phaseolin, G1-globulin) of the French bean was isolated from a genomic library constructed in the phage vector Charon 24A. Comparison of the nucleotide sequence of part of the gene with that of the cloned messenger RNA (cDNA) revealed the presence of three intervening sequences, all beginning with GTand ending with AG. The 5′; and 3′ boundaries of intervening sequences TVS-A (88 base pairs) and IVS-B (124 base pairs) are similar to those described for animal and viral genes, but the 3′ boundary of IVS-C (129 base pairs) shows some differences. A sequence of 185 amino acids deduced from the cloned DMAs represents about 40% of a phaseolin polypeptide.

124 citations


Journal ArticleDOI
TL;DR: The data demonstrated that there were multiple copies, perhaps 10 or more, of argininosuccinate synthetase-like sequences in human DNA and that the canavanine-resistant phenotype was not due to gene amplification.

114 citations


Journal ArticleDOI
24 Dec 1981-Nature
TL;DR: Sequence homologies among the four exons that constitute a single domain suggest that they were derived, at least in part, from a common sequence which underwent successive amplification and divergence in the murine α-fetoprotein gene.
Abstract: The DNA sequences of the 14 exon junctions in the murine α-fetoprotein gene were determined using cloned genomic DNA. When these exons were examined with respect to the polypeptide segments they encoded, a direct correspondence between a threefold repeat of four exons and three protein domains was observed. Nucleotide sequence comparisons among the four exons of each domain were used to deduce the likely structure of the primordial domain, and the order and mechanism of its triplication to form the tripartite ancestral gene from which both α-fetoprotein and serum albumin arose. Sequence homologies among the four exons that constitute a single domain also suggest that they were derived, at least in part, from a common sequence which underwent successive amplification and divergence.

99 citations


Journal ArticleDOI
TL;DR: Restriction endonuclease mapping and DNA sequence determination of the recombinant phage and comparison to total genomic DNA confirmed that the genes are in tandem, 13.5 kilobase pairs apart, and they are transcribed from the same strand of DNA.
Abstract: The urine alpha-fetoprotein (AFP) and serum albumin genes most probably arose in evolution as the consequence of a duplication of a common ancestral gene. They have both been previously mapped to chromosome 5 in the mouse. We now have evidence that these genes are closely linked. By using a unique copy DNA probe derived from previously cloned AFP 5' flanking DNA, a recombinant DNA phage has been isolated, from a bacteriophage DNA library, that contains sequences flanking the 5' end of the AFP gene and the 3' end of the albumin gene. Restriction endonuclease mapping and DNA sequence determination of the recombinant phage and comparison to total genomic DNA confirmed that the genes are in tandem, 13.5 kilobase pairs apart, with the albumin gene to the 5' side of the AFP gene. Thus, they are transcribed from the same strand of DNA.

99 citations


Journal ArticleDOI
01 Mar 1981-Cell
TL;DR: It is determined that U1 RNA is synthesized by polymerase II; however, a "Hogness box" is not present upstream from its cap site at the position usually observed for mRNA genes.

Journal ArticleDOI
TL;DR: A 7.5 kb Hsu I restriction fragment of genomic DNA containing a beta-globin gene has been isolated from a patient doubly heterozygous for beta + thalassaemia and a delta beta (Lepore globin fusion gene), and may result in a precursor mRNA less amenable to RNA splicing than its normal counterpart.
Abstract: A 7.5 kb Hsu I restriction fragment of genomic DNA containing a beta-globin gene has been isolated from a patient doubly heterozygous for beta + thalassaemia and a delta beta (Lepore globin fusion gene. This fragment must be derived from the chromosome carrying the beta +-thalassaemia determinant. The gross structure of the cloned gene plus flanking sequences is indistinguishable from that of a normal beta-globin gene. Within in 1606 base-pair transcribed region of the gene there is only one nucleotide difference from the normal beta-globin gene sequence. This is a G leads to A replacement 21 nucleotides upstream from the 3' terminus of the small intron. This nucleotide lies within a 10 base-pair sequence repeated in an inverted configuration near the 5' terminus of the small intron. The nucleotide replacement may result in a precursor mRNA less amenable to RNA splicing than its normal counterpart.

Journal ArticleDOI
01 Mar 1981-Gene
TL;DR: The data indicate the repetitive DNA sequences, members of the Alu family of interpersed 300 bp reiterated DNA, are imbedded in both templates and the RNAs transcribed from them are composed of an entire AlU family sequence.

Journal ArticleDOI
01 Jan 1981-Nature
TL;DR: A 0.8-kilobase poly(A)-containing RNA is transcribed from the cloned Drosophila segment in transformed yeast cells and can account for functional expression of the gene.
Abstract: Transformation of mutant yeast cells by cloned genomic DNA from a higher eukaryote has made it possible to isolate a Drosophila DNA sequence that complements a yeast adenine-8-mutation. A 0.8-kilobase poly(A)-containing RNA is transcribed from the cloned Drosophila segment in transformed yeast cells and can account for functional expression of the gene.

Journal ArticleDOI
01 Apr 1981-Cell
TL;DR: In this article, four Drosophila alpha-tubulin genes have been isolated on recombinant DNA molecules and the identity of two of these genes (T alpha 1 and T alpha 2) was established by isolating complementary mRNAs and then examining the in vitro translation products of the mRNA.

Journal ArticleDOI
TL;DR: In this paper, annealing studies were performed on DNA fragments associated with rat and mouse liver interphase nuclear matrix and the metaphase scaffold of Chinese hamster DON cells.
Abstract: Annealing studies were performed on DNA fragments associated with rat and mouse liver interphase nuclear matrix and the metaphase scaffold of Chinese hamster DON cells. Matrix and scaffold bound DNA fragments, reassociated with an excess of total genomic DNA, displayed kinetics virtually identical with total nuclear DNA probes. Moreover, both the extent and kinetics of these hybridizations were independent of the matrix DNA fragment size (less than 350--5000 base pairs) and the method of nuclease digestion used in their preparation (DNase I, micrococcal nuclease or endogenous digestion). The repetitive DNA component of the matrix DNA was examined by reacting discrete sizes of matrix DNA fragments (less than 350--5000 base pairs) from mouse liver with a library of cloned repetitive sequence DNA fragments which included mouse major satellite sequences. Our results demonstrate that short DNA fragments anchored to the nuclear matrix contain these cloned sequences is similar proportion of total nuclear DNA and, when viewed in light of the annealing results, indicate that matrix DNA is not enriched in either repetitive or unique sequences. Furthermore, the matrix DNA fragments appear to contain the entire sequence complexity of the genome. Finally, we hybridized both matrix and total nuclear DNA fragments with cDNA to total nuclear polyadenylated RNA. The kinetics and extent of hybridization indicate that most, if not all, of the actively transcribed DNA sequences are present in similar concentrations. We conclude that in the overall organization of eukaryotic DNA within the nucleus, the repeating domains or loops which have been demonstrated by a number of investigators are not anchored at specific attachment sequences in interphase cells or during mitosis. These findings are discussed with regard to current concepts of eukaryotic DNA loop organization.

Journal ArticleDOI
TL;DR: Having isolated a chromosomal human fibroblast interferon gene from a gene bank, it is concluded from nucleotide sequencing studies that there is a complete absence of introns within the RNA-coding region.
Abstract: Experiments in which immobilised restriction fragments of genomic DNA were hybridised with a cloned human fibroblast interferon cDNA indicate that the homologous chromosomal genes exist in only one basic arrangement. This is in marked contrast to recent studies by Nagata et al. (1) showing that there are at least eight gene arrangements for human leukocyte interferon. Having isolated a chromosomal human fibroblast interferon gene from a gene bank, we conclude from nucleotide sequencing studies that there is a complete absence of introns within the RNA-coding region. In view of a similar observation recently made for a human leukocyte interferon gene (1), it would appear as if interferon genes in general are unlike the vast majority of eukaryote genes in this respect.

Journal Article
01 Jan 1981-Scopus
TL;DR: In the overall organization of eukaryotic DNA within the nucleus, the repeating domains or loops which have been demonstrated by a number of investigators are not anchored at specific attachment sequences in interphase cells or during mitosis.
Abstract: Annealing studies were performed on DNA fragments associated with rat and mouse liver interphase nuclear matrix and the metaphase scaffold of Chinese hamster DON cells. Matrix and scaffold bound DNA fragments, reassociated with an excess of total genomic DNA, displayed kinetics virtually identical with total nuclear DNA probes. Moreover, both the extent and kinetics of these hybridizations were independent of the matrix DNA fragment size (less than 350--5000 base pairs) and the method of nuclease digestion used in their preparation (DNase I, micrococcal nuclease or endogenous digestion). The repetitive DNA component of the matrix DNA was examined by reacting discrete sizes of matrix DNA fragments (less than 350--5000 base pairs) from mouse liver with a library of cloned repetitive sequence DNA fragments which included mouse major satellite sequences. Our results demonstrate that short DNA fragments anchored to the nuclear matrix contain these cloned sequences is similar proportion of total nuclear DNA and, when viewed in light of the annealing results, indicate that matrix DNA is not enriched in either repetitive or unique sequences. Furthermore, the matrix DNA fragments appear to contain the entire sequence complexity of the genome. Finally, we hybridized both matrix and total nuclear DNA fragments with cDNA to total nuclear polyadenylated RNA. The kinetics and extent of hybridization indicate that most, if not all, of the actively transcribed DNA sequences are present in similar concentrations. We conclude that in the overall organization of eukaryotic DNA within the nucleus, the repeating domains or loops which have been demonstrated by a number of investigators are not anchored at specific attachment sequences in interphase cells or during mitosis. These findings are discussed with regard to current concepts of eukaryotic DNA loop organization.

Journal ArticleDOI
TL;DR: A new technique for selection of cloned gene segments which are expressed preferentially at one developmental stage but at a relatively low level is described, and a number of new clones are novel, in that they encode multiple discrete mRNA species all of which accumulate only at the cell aggregate stages.
Abstract: We describe a new technique for selection of cloned gene segments which are expressed preferentially at one developmental stage but at a relatively low level. A nitrocellulose filter replica of plaques of lambda phage which contain approximately 8 KB inserts of genomic DNA is prepared; it is hybridized with a small amount of [32p] labeled mRNA prepared from one developmental stage, in the presence of a several-hundred fold excess of competitor RNA from a different stage. We show that clones of Dictyostelium nuclear DNA which form hybrids under these conditions indeed encode developmentally regulated mRNAs. Our previous analysis of Dictyostelium discoideum differentiation indicated that transcripts from about 12% of the genome appear in mRNA at one defined stage of differentiation - the formation of cell-cell aggregates. A number of our new clones are novel, in that they encode multiple discrete mRNA species all of which accumulate only at the cell aggregate stages; others encode one or more mRNAs which appear at the tight aggregate stage and also one or more which are present throughout differentiation. These latter clones, in particular, would be difficult to identify using other selection techniques.

Journal ArticleDOI
TL;DR: A rat genomic DNA clone containing the 5’ flanking region, three exons, two introns, and a portion of a third intron of the rat prolactin gene was isolated and characterized and suggested that transcription is initiated 54 nucleotides upstream from the initiator methionine codon.

Journal ArticleDOI
TL;DR: In this article, the multiplicity, heterogeneity, and organization of the genes encoding the sea urchin Lytechinus pictus by using cloned complementary deoxyribonucleic acid (cDNA) and genomic tubulin sequences were analyzed.
Abstract: The authors analyzed the multiplicity, heterogeneity, and organization of the genes encoding the ..cap alpha.. and ..beta.. tubulins in the sea urchin Lytechinus pictus by using cloned complementary deoxyribonucleic acid (cDNA) and genomic tubulin sequences. cDNA clones were constructed by using immature spermatogenic testis polyadenylic acid-containing ribonucleic acid as a template. ..cap alpha.. and ..beta..-tubulin clones were identified by hybrid selection and in vitro translation of the corresponding messenger ribonucleic acids, followed by immunoprecipitation and two-dimensional gel electrophoresis of the translation products. The ..cap alpha.. cDNA clone contains a sequence that encodes the 48 C-terminal amino acids of ..cap alpha.. tubulin and 104 base pairs of the 3' nontranslated portion of the messenger ribonucleic acid. The ..beta.. cDNA insertion contains the coding sequence for the 100 C-terminal amino acids of ..beta.. tubulin and 83 base pairs of the 3' noncoding sequence. Hybrid selections performed at different criteria demonstrated the presence of several heterogeneous, closely related tubulin messenger ribonucleic acids, suggesting the existence of heterogeneous ..cap alpha..- and ..beta..-tubulin genes. Hybridization analyses indicated that there are at least 9 to 13 sequences for each of the two tubulin gene families per haploid genome. Hybridization of the cDNA probes to both totalmore » genomic DNA and cloned germline DNA fragments gave no evidence for close physical linkage of ..cap alpha..-tubulin genes with ..beta..-tubulin genes at the DNA level. In contrast, these experiments indicated that some genes within the same family are clustered.« less

Journal ArticleDOI
05 Feb 1981-Nature
TL;DR: In this paper, a leghaemoglobins (Lb) cDNA recombinant molecule, pLb1, was used to isolate two genomic Lb sequences from a library constructed in Charon 4.
Abstract: The leghaemoglobins (Lb) are myoglobin-like proteins found in all nitrogen-fixing root nodules of legumes1–3. They are encoded by plant nuclear genes4 which are specifically induced and form the predominant protein in nodules developed in symbiosis with the appropriate species of Rhizobium. The Lb is located in the host-cell cytoplasm of the infected cell5 and is thought to facilitate oxygen diffusion6,7. Amino acid sequencing of the soybean Lbs has revealed at least four primary structures differing only in a few amino acids8–10. We have previously estimated about 40 copies of Lb sequences in the soybean (Glycine max L.) genome by cDNA hybridization4. To investigate Lb gene organization and function, we prepared and characterized a Lb cDNA recombinant molecule, pLb1, and used it to isolate two genomic Lb sequences from a library constructed in Charon 4. We report here that the organization of the two genomic Lb sequences is quite distinct and one of them seems to have an intervening sequence(s). Hybridization of pLb1 with genomic DNA from various tissues showed that Lb sequences are dispersed through more than 30 kilobases of genomic DNA and that there is no apparent sequence rearrangement or methylation changes following induction of Lb genes.

Journal ArticleDOI
TL;DR: Restriction enzyme analyses of the total DNA and the satellite I fragment show that three HpaII sites in the fragment are completely unmethylated in sperm but fully methylated in thymus DNA, which can probably account for the lower level of methylation of sperm DNA rather than hemimethylation as previously suggested.
Abstract: Genomic DNA of calf thymus contains 15 times as much 5-methylcytosine as similar sperm DNA, but the major EcoRI repeat fragment from satellite I of thymus contains ten times as much 5-methylcytosine as the corresponding fragment from sperm DNA Restriction enzyme analyses of the total DNA and the satellite I fragment show that three HpaII sites in the fragment are completely unmethylated in sperm but fully methylated in thymus DNA Under-methylation of many sites in the satellite DNAs can probably account for the lower level of methylation of sperm DNA rather than hemimethylation as previously suggested These results are also discussed in relation to maintenance and de novo (initiation-type) methylases

Journal ArticleDOI
TL;DR: Analysis of numerous geographically distinct isogenic lines suggests that Dm 25 patterns are determined by germ-line factors and are not the product of strictly somatic events.
Abstract: The location of sequences homologous to a cloned D. melanogaster DNA segment, Dm 25, has been examined in polytene chromosomes by hybridization in situ. Dm 25 localizes to multiple sites and shows variation in patterns between different strains and among individuals within wild-type laboratory strains. Analysis of numerous geographically distinct isogenic lines suggests that Dm 25 patterns are determined by germ-line factors and are not the product of strictly somatic events. In general there is wide variation in Dm 25 patterns among different lines, but a significant number of sites are common to two or more distinct lines. Hybridization to restriction digests of genomic DNA suggests that Dm 25 is a moderately repetitive, conserved sequence whose copies are dispersed throughout the genome. Analysis of species other than melanogaster indicates a significant divergence in structure of sequences homologous to Dm 25 as well as a drastic reduction in amount of homology to the melanogaster sequence.

Journal ArticleDOI
TL;DR: The expression of the integrated viral genomes in transformed and tumor cell lines was regulated by mechanisms more complicated than simple gene dosage effects, and virus-associated RNA represents a population of low-molecular-weight RNAs that map at around 30 fractional length units on the viral genome.
Abstract: The expression as cytoplasmic RNA of integrated human adenovirus type 12 (Ad12) DNA in transformed and tumor cell lines and in revertants was investigated The transformed and tumor cells contained multiple copies of the viral genome, 3 to 22 copies per cell in different cell lines The integrated Ad12 DNA molecules persisted intact or nearly intact and in most cases colinear with the virion DNA In the revertant cell lines, which were derived from cell line T637 (22 copies of Ad12 DNA per cell), all of the Ad12 DNA molecules were lost (line F10) or only one copy and a fraction of a second copy persisted (line TR12) The size classes and map locations of Ad12-specific cytoplasmic RNAs in three Ad12-transformed hamster cell lines (T637, HA12/7, and A2497-3), in two revertant lines (F10 and TR12), in one Ad12-induced hamster (CLAC3), and in one rat brain tumor line (RBT12/3) were determined Cytoplasmic RNA from uninfected B3 hamster cells and from human KB cells productively infected with Ad12 served as controls In the latter control experiments, the RNA was isolated early or late postinfection With respect to the amounts of Ad12-specific RNAs detected in cytoplasmic RNA from various Ad12-transformed or Ad12-induced tumor cell lines, we could not establish any correlations to the number of Ad12 genome copies integrated into the cellular DNAs Thus, the expression of the integrated viral genomes in these lines was regulated by mechanisms more complicated than simple gene dosage effects Using cloned fragments of Ad12 DNA as hybridization probes, we analyzed the cytoplasmic RNAs from the cell lines mentioned by electrophoresis on agarose gels, blotting, and DNA-RNA hybridization For each transformed and tumor cell line, except for the revertants, several size classes of Ad12-specific cytoplasmic RNA were detected for the early E1, E2, and E4 regions of Ad12 DNA Some of these size classes were similar but not identical to those observed in cytoplasmic RNA isolated early from human KB cells productively infected with Ad12 Only cell lines A2497-3, T637, and RBT12/3 contained several size classes of cytoplasmic RNA homologous to the E3 region of Ad12 DNA Weak homologies to the E1 region of Ad12 DNA were also detected in the revertant lines F10 and TR12 Late regions of Ad12 DNA were expressed as cytoplasmic RNA in cell lines CLAC3 and RBT12/3 Weak homologies were detected between certain segments of the Ad12 genome (the Eco RI-B, -C, and -D fragments) and the cytoplasmic RNA from uninfected hamster cells These homologies had no apparent counterpart at the level of DNA, perhaps because these homologies could be detected only due to an overrepresentation of RNA sequences In preliminary experiments, we failed to detect the expression as cytoplasmic RNA of the so-called virus-associated RNA in transformed and tumor cell lines Virus-associated RNA represents a population of low-molecular-weight RNAs that map at around 30 fractional length units on the viral genome Images

Journal Article
TL;DR: Three strains of Rhizobium japonicum were examined for the presence of interspecific conserved plasmid-borne DNA sequences and the location of their nif DNA sequences, and heterologous hybridizations between plasmids and total DNAs from these strains and DNA from strain 110 suggest that several sequences which are plasmod-borne in one strain can occur in the chromosome or in very large plasmID(s) in the other strains.
Abstract: Three strains of Rhizobium japonicum were examined for the presence of interspecific conserved plasmid-borne DNA sequences and the location of their nif DNA sequences. Strains 61A76 and 110, which both form effective (nitrogen fixing) nodules on soybeans show very low (24%) total DNA sequence homology with each other; strain 61A76 contains one plasmid, and strain 110 contains no identifiable plasmids. Strain 61A24 which forms ineffective nodules on soybeans shows relatively high (50%) sequence homology to strain 110 and contains two plasmids. While the total sequence homology between purified plasmid DNA isolated from strains 61A76 and 61A24 appears limited, heterologous hybridizations between plasmids and total DNAs from these strains and DNA from strain 110 suggest that several sequences which are plasmid-borne in one strain can occur in the chromosome or in very large plasmid(s) in the other strains. The plasmid isolated from strain 61A24 exhibits some homology with several SmaI fragments of an octopine Ti plasmid from Agrobacterium tumifaciens, whereas the 61A76 plasmid shows no homology to this Ti plasmid. DNA sequences from five strains of Rhizobium japonicum were found to hybridize with pSA30, a plasmid carrying the Klebsiella pneumoniae nif-KDH genes, but these sequences were not located on the isolated plasmids. The organization of these genes appears to be similar in strains 110 and 61A24, but is different in strain 61A76.

Journal ArticleDOI
01 Apr 1981-Cell
TL;DR: The data are consistent with the hypothesis that dm and HSRs in these cells contain amplified genes and sequences homologous to the cloned fragments are approximately 100- to 200-fold more abundant in the genome of the Y1-DM cells than in the parental mouse cells.

Journal ArticleDOI
TL;DR: Using a full-length uteroglobin cDNA clone as a specific hybridization probe, recombinant lambda phages containing the entire chromosomal uteroglobin gene have been isolated from a rabbit genomic DNA library and revealed the presence of uteroglobin mRNA precursors.

Journal ArticleDOI
TL;DR: The results indicate that the levels of the primary transcript of alpha 2 collagen RNA are much lower in RSV-CEF than in CEF, and suggest, but do not prove, that the effect of the transforming protein p60src on the synthesis ofalpha 2 collagen is mediated by a transcriptional control mechanism.
Abstract: We have examined the levels of type I alpha 2 collagen RNA precursors, containing both intron and exon sequences in nuclear RNA preparations of chick embryo fibroblasts (CEF) and of CEF transformed by the Schmidt-Rupin strain of Rous sarcoma virus (RSV). We have used two different fragments of chick alpha 2 collagen genomic DNA as hybridization probes in S1 mapping experiments. Each of these DNA probes contains an entire intron. Our results indicate that the levels of the primary transcript of alpha 2 collagen RNA are much lower in RSV-CEF than in CEF. They suggest, but do not prove that the effect of the transforming protein p60src on the synthesis of alpha 2 collagen is mediated by a transcriptional control mechanism.

Journal ArticleDOI
TL;DR: Comparison of restriction enzyme digests of genomic DNA prepared from lens and non-lens tissues showed that the delta-crystallin gene sequences are not grossly rearranged in the lens during development, and results associate delta- Crystallin genes transcription and site-specific hypomethylation of the Delta-Crystallin DNA.