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Showing papers on "genomic DNA published in 1980"


Journal ArticleDOI
01 May 1980-Cell
TL;DR: Bacterial clones containing inserted DNA sequences specific for α- Tubulin, β-tubulin,β-Actin and γ-actin have been constructed from mRNA of embryonic chick brain and are able to hybridize under stringent conditions to DNA of all vertebrates tested, as well as to sea urchin DNA, but not to yeast DNA.

1,650 citations


Journal ArticleDOI
01 Dec 1980-Cell
TL;DR: The hamster gene coding for the enzyme adenine phosphoribosyl transferase (aprt) is isolated using gene transfer and molecular cloning of transforming DNA and sequences homologous to this clone are present in all hamster aprt+ transformants examined.

423 citations


Journal ArticleDOI
01 Feb 1980-Cell
TL;DR: In vitro translation of mRNA selected hybridization by a DNA segment specific to lambda DmA2 suggests that this particular gene codes for one of the cytoplasmic actin polypeptides.

399 citations


Journal ArticleDOI
11 Dec 1980-Nature
TL;DR: A segment of a DNA encoding most of POMC is isolated, using as probe a mouse 144-base pair cloned cDNA fragment encoding β-MSH and β-endorphin, and this may indicate an as yet unrecognized biological function(s) for the NH2-terminal portion of the 16K fragment.
Abstract: The peptide hormones ACTH, beta-endorphin, alpha- and beta-melanotropin(MSH) and possibly gamma-MSH are synthesized in the pituitary gland by the processing of a 32,000-molecular weight (MW) polypeptide called proopiomelanocortin (POMC) The existence of a further precursor (pre form) to POMC containing an additional N-terminal 'leader' peptide has been suggested by analysis of the in vitro translation products of poly(A)-containing RNA from AtT-20 cells, a mouse ACTH-producing cell line of pituitary origin Nakanishi et al cloned and sequenced a cDNA copy of the bovine prePOMC mRNA This sequence confirmed the known structure of the carboxyl half of POMC and revealed the presence of a new MSH-like moiety, gamma-MSH, within the 16,000-MW amino half of the precursor (16K fragment) Recent experiments have suggested that this peptide may act in synergy with ACTH to increase corticosterone and aldosterone production in vivo and in vitro We have now isolated from a rat genomic DNA library a segment of a DNA encoding most of POMC, using as probe a mouse 144-base pair cloned cDNA fragment encoding beta-MSH and beta-endorphin The cloned rat gene is one of two (or more) closely related POMC genes The DNA sequence obtained shows that the cloned POMC gene is not interrupted by any intervening sequence (IVS) between the codon for amino acid 19 and the presumptive poly(A) addition site This region of POMC encodes all the biologically active peptides mentioned above The DNA sequence encoding the putative gamma-MSH and the coding sequence that precedes it are highly conserved between rat and cow This may indicate an as yet unrecognized biological function(s) for the NH2-terminal portion of the 16K fragment

296 citations


Journal ArticleDOI
19 Sep 1980-Science
TL;DR: The sequence of a human leukocyte-derived complementary DNA, Hif-2h, which directs the formation in Escherichia coli of a polypeptide, IFN-alpha 1, with interferon (IFN) activity has been described, revealing the presence of at least eightIFN-related genes.
Abstract: The sequence of a human leukocyte-derived complementary DNA (cDNA), Hif-2h, which directs the formation in Escherichia coli of a polypeptide, IFN-alpha 1, with interferon (IFN) activity has been described. A second IFN cDNA, Hif-SN206, which also elicits synthesis of a biologically active IFN, IFN-alpha 2, is described in this article. Whereas IFN-alpha 2 is twice as active on human as on bovine cells, IFN-alpha 1 is 10 to 20 times more active on bovine than on human cells. As deduced from the cDNA's, the messenger RNA's for the two IFN's differ in length and in 20 percent of the nucleotides; the mature IFN polypeptides differ in 17 percent of the amino acids. Both IFN-alpha 1 and IFN-alpha 2 differ from the lymphoblastoid IFN described by others. Therefore, at least three different IFN-alpha genes are expressed in man; studies on genomic DNA reveal the presence of at least eight IFN-related genes.

270 citations


Journal ArticleDOI
TL;DR: A library of genomic DNA segments has been constructed from the DNA of a somatic cell hybrid carrying a portion of human chromosome 11 on a Chinese hamster ovary cell background, and using a nucleic acid hybridization technique that distinguishes human and Chinese hamsters interspersed, repetitive DNA, this approach promises implications for human genetics generally, for the human genetic diseases, and possibly for understanding of gene regulation in normal and abnormal differentiation.
Abstract: Recombinant DNA techniques have been combined with somatic cell genetic methods to identify, isolate, and amplify fragments of human DNA localized at specific regions of human chromosome 11 selected as a model system. A library of genomic DNA segments has been constructed, in λ Charon 4A bacteriophage, from the DNA of a somatic cell hybrid carrying a portion of human chromosome 11 on a Chinese hamster ovary cell background. Using a nucleic acid hybridization technique that distinguishes human and Chinese hamster interspersed, repetitive DNA, we have been able to distinguish recombinant phages carrying DNA segments of human origin from recombinant phages carrying DNA segments of Chinese hamster origin. We have isolated 50 human DNA segments thus far and have characterized 5 in detail. For each DNA segment characterized, a subsegment that carries no repetitive human DNA sequences has been identified. These segments have been used as hybridization probes in experiments that localize the DNA fragment on the chromosome. In each case an unequivocal chromosomal localization has been obtained with reference to a panel of hybrid cell clones each of which carries a deletion of a portion of the short arm of chromosome 11. At least one DNA segment has been identified which maps to each of the four regions on the short arm defined by the panel of hybrid cell clones used. The approaches described here appear to be general. They can be extended to produce a fine structure map of human chromosome 11 and other human chromosomes. This approach promises implications for human genetics generally, for the human genetic diseases, and possibly for understanding of gene regulation in normal and abnormal differentiation.

187 citations


Journal ArticleDOI
TL;DR: A human genomic DNA segment encoding the corticotropin-beta-lipotropin precursor peptide from a fetal DNA library is isolated, using previously cloned bovine cDNA for this peptide as a probe.
Abstract: We have isolated a human genomic DNA segment encoding the corticotropin-beta-lipotropin precursor peptide from a fetal DNA library, using previously cloned bovine cDNA for this peptide as a probe. The human genomic DNA was studied by electron microscope heteroduplex analysis and gel blotting methods, and its nucleotide sequence was determined and compared with that of cDNA corresponding to bovine pro-opiomelanocortin mRNA. From this sequence, segments of interspecies conservation and divergence, punctuated by pairs of the basic amino acid residues lysine and arginine, were identified. No noncoding intervening sequence was observed over an 830-base-pair DNA segment extending from a position near the 5' end of the structural pro-opiomelanocortin gene through the 3' terminus of the cDNA and including sequences for the component peptide hormones corticotropin and beta-lipotropin.

161 citations


Journal ArticleDOI
11 Jul 1980-Science
TL;DR: The human genes for growth hormone, chorionic somatomammotropin, and a third growth hormone-like gene (GHL) have been located on chromosome 17 in humans and a 7.5-kilobase DNA fragment related to growth hormone DNA sequences was found in mouse cells.
Abstract: The human genes for growth hormone (GH), chorionic somatomammotropin (CSH), and a third growth hormone-like gene (GHL) have been located on chromosome 17 in humans. DNA fragments of 2.6, 2.8, and 9.5 kilobase pairs containing GH, CSH, and GHL, respectively, were identified in human genomic DNA, and a 7.5-kilobase DNA fragment related to growth hormone DNA sequences was found in mouse cells. In somatic hybrids of human and mouse cells containing reduced numbers of human chromosomes, but a normal complement of mouse chromosomes, the mouse, 7.5-kolobase DNA fragment was always present, whereas the 2.6-, 2.8-, and 9.5-kilobase human fragments were present only when human chromosome 17 was also present.

154 citations


Journal ArticleDOI
01 Aug 1980-Cell
TL;DR: Clones containing five non-adult β-globin genes were isolated from a library of BALB/c DNA and formed a contiguous block of 32 kb of the mouse genome, establishing the physical linkage of these non- adult genes to the two adult β- globin genes as well as of the twoadult genes to each other.

141 citations


Journal ArticleDOI
11 Sep 1980-Nature
TL;DR: Analysis of cloned rat genomic DNA fragments using cloned cDNA probes indicates that the rat genome contains multiple closely related amylase genes in which the cDNA sequences are distributed within a region 9 kilobases in length and are interrupted by at least seven intervening sequences.
Abstract: The sequences of two cloned rat pancreatic amylase cDNAs comprising 95% of the mRNA sequence are reported. Analysis of cloned rat genomic DNA fragments using cloned cDNA probes indicates that the rat genome contains multiple closely related amylase genes in which the cDNA sequences are distributed within a region 9 kilobases in length and are interrupted by at least seven intervening sequences.

135 citations


Journal ArticleDOI
TL;DR: An unusually long repeated DNA sequence was identified in cloned DNA, three kb 3' to the human beta-globin gene, which does not appear to be composed of any smaller tandemly repeated subunits, nor is it expressed at a high level in bone marrow cell RNA.
Abstract: An unusually long repeated DNA sequence was identified in cloned DNA, three kb 3' to the human beta-globin gene. Other members of this repeated sequence family were isolated from a human genomic DNA library and characterized by Southern blotting techniques, electron microscopy, and solution hybridization. The copy located next to the beta-globin gene was found to be 6.4 +/- 0.2 kb long and continuous over that length. This repeated sequence family comprises about 1% of the human genome and contains 3000-4800 copies of moderate sequence divergence which are interspersed with other less-highly repeated DNA. The 6.4 kb repeated unit does not appear to be composed of any smaller tandemly repeated subunits, nor is it expressed at a high level in bone marrow cell RNA.

Journal ArticleDOI
01 Feb 1980-Cell
TL;DR: The results provide the first demonstration of the relationship between single-copy and repetitive DNA sequences in a large segment of chromosomal DNA containing a well characterized set of developmentally regulated genes.

Journal ArticleDOI
TL;DR: It is concluded that the transforming region and the sequences that code for the viral p21 protein are both located within the 2 kilobases closest to the 5' end of the Ha-MuSV genome.
Abstract: The comparative infectivity of Harvey murine sarcoma virus (Ha-MuSV) DNA for NIH 3T3 cells was determined for supercoiled Ha-MuSV DNA molecularly cloned in lambda phage and pBR322 at its unique EcoRI site (which is located near the middle of the 6-kilobase pair [kbp] unintegrated linear viral DNA) and for two cloned subgenomic fragments: one was 3.8 kbp and lacked about 1 kbp from each side of the EcoRI site, and the second did not contain the 3 kbp of the unintegrated linear viral DNA located on the 3' side of the EcoRI site. Each subgenomic DNA induced foci of transformed cells, but with a lower relative efficiency then genomic DNA. Transfection with intact vector Ha-MuSV DNA yielded results similar to those obtained after separation of Ha-MuSV DNA from vector DNA. Cells lines were then derived from individual foci transformed with each type of viral DNA. Focus-forming virus was recovered from transformed cells after superinfection with a helper-independent virus, but the efficiency varied by several orders of magnitude. For several transformed lines, the efficiency of recovery of focus-forming virus was correlated with the structure of the Ha-MuSV DNA in the cells before superinfection. When 32P-labeled Ha-MuSV DNA probes specific for sequences on either the 3' or 5' side of the EcoRI site were used to analyze the viral RNA in the transformed cell lines, all lines were found to hybridize with the 5' probe, but some lines did not hybridize with the 3' probe. The transformed lines contained high levels of the Ha-MuSV-coded p21 or its associated GDP-binding activity. We conclude that the transforming region and the sequences that code for the viral p21 protein are both located within the 2 kilobases closest to the 5' end of the Ha-MuSV genome.

Journal ArticleDOI
01 Nov 1980-Gene
TL;DR: The construction of a cosmid, MUA-3, designed for the convenient cloning of eukaryotic DNA segments up to 48 kb in length is described, and the efficiency of producing clones by a partial restriction and ligation method is shown to be over 3 X 10(5) clones/microgram of Drosophila DNA.

Journal ArticleDOI
TL;DR: The structural analysis of the 2.0 kb region upstream from the epsilon-globin gene has been carried out and a new technique was developed to precisely map a reiterated DNA sequence present 1.5 kb to the 5' side of the gene.
Abstract: The structural analysis of the 2.0 kb region upstream from the έ-globin gene has been carried out. A genomic DNA map around the gene was worked out in some detail to ensure that the cloned DNA was representative of the actual chromosomal arrangement. Furthermore, a new technique was developed to precisely map a reiterated DNA sequence present 1.5 kb to the 5' side of the gene. The complete nucleotide sequence of the 2.0 kb 5' flanking region was then determined and overlapped with the gene. The sequence included the reiterated DNA sequence which is homologous to the so-called AluI family of repeats. Unusual stretches of sequence 50 nucleotides long, where A + T represent about 90% of the bases, are present at both the 5' and 3' sides of the repeat.

Journal ArticleDOI
TL;DR: Electron microscopic analysis of hybrids between type I alpha 2 collagen mRNA and the overlapping genomic clones indicates that the chickenalpha 2 collagen gene has a length of at least 37 kilobases, about 7.4 times longer than the corresponding translatable cytoplasmic mRNA.
Abstract: A series of overlapping recombinant clones, which cover the alpha 2 (type I) collagen gene, have been isolated by stepwise screening of two libraries of chicken genomic DNA fragments. The first genomic clone was isolated by using a cloned cDNA containing alpha 2 collagen DNA sequences as hybridization probe. The other clones were obtained by a sequence of screenings using defined fragments of the successive genomic clones as hybridization probes. Several types of experiments indicated that the DNA of these clones are truly overlapping and span 55 kilobase pairs of contiguous DNA sequences in the chicken genome. Sequence analysis of small DNA segments of some of these clones confirm that they contain coding sequences which specify alpha 2 collagen. Electron microscopic analysis of hybrids between type I alpha 2 collagen mRNA and the overlapping genomic clones indicates that the chicken alpha 2 collagen gene has a length of at least 37 kilobases, about 7.4 times longer than the corresponding translatable cytoplasmic mRNA. The coding information for alpha 2 collagen is distributed in more than 50 coding sequences which are interrupted by intervening sequences of various sizes. The structure of the gene implies that the conversion of precursor RNA to mature mRNA for alpha 2 collagen includes at least 50 splicing events.

Journal ArticleDOI
05 Sep 1980-Science
TL;DR: A 15,8-kilobase pair fragment of BALB/c mouse liver DNA, cloned in the Charon 4A lambda phage vector system, was shown to contain the mu heavy chain constant region (CHmu) gene for the mouse immunoglobulin M.
Abstract: A 15,8-kilobase pair fragment of BALB/c mouse liver DNA, cloned in the Charon 4A lambda phage vector system, was shown to contain the mu heavy chain constant region (CHmu) gene for the mouse immunoglobulin M. In addition, this fragment of DNA contains at least two J genes, used to code for the carboxyl terminal portion of heavy chain variable regions. These genes are located in genomic DNA about eight kilobase pairs to the 5' side of the CHmu gene. The complete nucleotide sequence of a 1120-base pair stretch of DNA that includes the two J genes has been determined.

Journal ArticleDOI
01 Sep 1980-Cell
TL;DR: The isolation of two recombinant λ phages, each containing genomic DNA fragments encoding both the major adult α- and β-globin mRNAs of X. laevis, shows that the α 1 - and β 1 -globin genes lie in the same orientation separated by 7.7 kb of DNA.

Journal ArticleDOI
TL;DR: The proviralDNA of both clones contains nucleotide sequences complementary to the 5' and 3' ends of proviral DNA; and the host DNA flanking one clone belongs to the unique class of genomic DNA, whereas the DNA flanked the second clone is reiterated at least 15 times within the mouse genome.
Abstract: Restriction fragments of the mouse mammary tumor virus (MMTV) proviral DNA were obtained by molecular cloning procedures. A 4-kilobase fragment delimited by two PstI sites was isolated from unintegrated, linear MMTV DNA and amplified in the pBr322 plasmid vector. EcoRI fragments of proviral DNA, integrated into the genome of a GR mammary tumor cell line, were isolated as lambda recombinant molecules. Five different recombinant phages which contained the 3' region of the MMTV proviral DNA and adjacent host DNA sequences were isolated. Heteroduplex analysis and S1 nuclease digestion suggested that there is no extensive sequence homology in the host DNA flanking the different proviral genes. The cloned DNA was fractionated into site-specific restriction fragments which served as molecular probes in the analysis of the endogenous MMTV proviral copies of C3H, GR, BALB/c, and feral mice. This allowed the correlation of MMTV-specific EcoRI fragments obtained from genomic DNA of these strains with the 5' and 3' ends of the proviral gene. Restriction fragments of two clones which contained the proviral sequences adjacent to the flanking host DNA as well as 1 to 2 kilobases of host DNA were used as hybridization probes, and the results allow the following conclusions: the proviral DNA of both clones contains nucleotide sequences complementary to the 5' and 3' ends of proviral DNA; and the host DNA flanking one clone belongs to the unique class of genomic DNA, whereas the DNA flanking the second clone is reiterated at least 15 times within the mouse genome.

Journal ArticleDOI
TL;DR: Southern transfer and solution hybridization experiments, using as probe a DNA fragment that encodes for Drosophila actin, demonstrate cross hybridization to DNA from the sea urchin Strongylocentrotus purpuratus.
Abstract: Southern transfer and solution hybridization experiments, using as probe a DNA fragment that encodes for Drosophila actin, demonstrate cross hybridization to DNA from the sea urchin Strongylocentrotus purpuratus. Recombinant DNA clones that contained sea urchin genomic DNA fragments were constructed and screened for the presence of actin-encoding DNA sequences by colony hybridization with the Drosophila actin sequence. Two different putative actin-encoding clones were identified and were shown to specifically hybridize actin-encoding mRNA from a complex mRNA population. Southern blot hybridization experiments with both the Drosophila actin sequence and one of the cloned sea urchin sequences, in conjunction with solution hybridization data, suggest an actin gene copy number of 5-20 per haploid genome. DNA sequence analysis of one of the cloned sequences indicates that this fragment codes for a cytoplasmic form of actin and contains an intervening sequence of at least 200 nucleotides beginning immediately after amino acid 121 in the protein sequence.

Journal ArticleDOI
20 Mar 1980-Nature
TL;DR: Restriction analysis of chicken DNA using probes derived from a cloned cDNA and analysis of cloned genomic DNA fragments containing δ-crystallin gene sequences have indicated the presence of at least two non-allelic genes forδ- Crystallin, the first and principal crystallin synthesised in the embryonic chicken lens.
Abstract: Restriction analysis of chicken DNA using probes derived from a cloned cDNA and analysis of cloned genomic DNA fragments containing δ-crystallin gene sequences have indicated the presence of at least two non-allelic genes for δ-crystallin, the first and principal crystallin synthesised in the embryonic chicken lens. Electron microscopic analyses of three cloned genomic fragments revealed that the δ-crystallin mRNA gene sequences are interrupted at least 14 times in one of the δ-crystallin genes.

Journal ArticleDOI
Richard Treisman1
TL;DR: The structures of the leader sequences strongly suggest that they are generated by appropriate splicing events from a tandemly repeated transcript of the entire circular viral genome.
Abstract: The leader sequences of two of the three polyoma virus late mRNAs were characterised by molecular cloning and DNA sequence analysis. A short single-stranded DNA fragment complementary to the 5' end of the body of mVP1 was used to prime cDNA synthesis, and double-stranded cDNA was inserted into a derivative of pAT 153. Analysis of fourteen mVP1 cDNAs and two mVP3 cDNAs allowed the precise determination of the leader-body joints, and demonstrated that the majority of polyoma late leader sequences consist of exact tandem repeats of a 57 nucleotide sequence present only once in the genomic DNA at 66-67 m.u. The sequences in the genomic DNA borderline this unit are typical of those found at RNA splice points. Leader sequences contained on average three to four repeat units. Nuclease S1 mapping of total late mRNA demonstrated that most mRNA 5' ends map heterogeneously in the 50 nucleotides 5' to the repeated sequence unit. The structures of the leader sequences strongly suggest that they are generated by appropriate splicing events from a tandemly repeated transcript of the entire circular viral genome.

Journal ArticleDOI
01 Dec 1980-Gene
TL;DR: Molecular hybridization, as well as comparison of the restriction maps, revealed the complete structural identity of the 3 μm DNA with a chromosomal repetitive unit of rDNA containing the genes for 25 S, 18 S, 5.8 S and 5 S rRNAs.

Journal ArticleDOI
TL;DR: The influenza virus-specific DNA sequences isolated from recombinant plasmid molecules were characterized by mapping restriction enzyme cleavage sites and the orientation of cloned DNA was determined with reference to the 3' terminus of viral RNA.
Abstract: DNA sequences corresponding to gene segments that code for the nonstructural protein, the matrix protein, and the hemagglutinin of influenza A virus [strain A/Udorn/72 (H3N2)] were cloned in Escherichia coli pBR 322. Initially, positive and negative cDNA strands were prepared separately by reverse transcription. The positive strands of cDNA were transcribed from genomic RNA segments by using a specific dodecamer DNA sequence as a primer; the negative strands of cDNA were transcribed from cytoplasmic viral mRNA segments by using an oligo(dT) primer. DNA duplexes corresponding in size to the virus RNA segments were then purified, inserted into the plasmid DNA, and used for transformation of E. coli. The influenza virus-specific DNA sequences isolated from recombinant plasmid molecules were characterized by mapping restriction enzyme cleavage sites. In addition, the orientation of cloned DNA was determined with reference to the 3' terminus of viral RNA.

Journal ArticleDOI
TL;DR: DNA sequence analysis of a small coding segment of lambda g COL 204 reveals a characteristic collagen type sequence which encodes for an amino acid sequence identical to a sequence found in calf alpha 2 collagen.
Abstract: We have isolated and characterized a segment of the chick alpha 2 collagen gene by screening a library of chick genomic fragments using as hybridization probe an alpha 2 collagen cDNA clone. Several clones were isolated and one of them, lambda gCOL 204, was used for further studies. The DNA of lambda gCOL 204 hybridizes to a unique species of mRNA the size of alpha 2 collagen mRNA. This mRNA can be translated into a unique polypeptide which comigrates in SDS-gel electrophoresis with pro-alpha 2 collagen. Electron microscopic analysis by R-loop technique indicates that lambda gCOL 204 contains 7Kb of the alpha 2 collagen gene. This 7 Kb piece constitutes the 3' end of the gene. The same clone also contains 9 Kb of DNA that is immediately adjacent to the 3' end of the alpha 2 collagen gene. The cloned segment of the alpha 2 collagen gene is interrupted by 8 intervening sequences of various lengths. The coding sequences for collagen in this clone add up to approximately 1,800 bp, which correspond to about 1/3 of alpha 2 collagen mRNA. DNA sequence analysis of a small coding segment of lambda g COL 204 reveals a characteristic collagen type sequence which encodes for an amino acid sequence identical to a sequence found in calf alpha 2 collagen. The sequence of this region of the protein has not yet been determined for the chick alpha 2 collagen.

Journal ArticleDOI
TL;DR: It is concluded that the distinct tissue-specific transcriptional regulation of this gene by steroids and iron levels in the oviduct and liver cannot be explained either by a multiplicity of genes or by somatic reorganization of the gene.

Journal ArticleDOI
TL;DR: DNA fragments, prepared by partial Eco RI digestion of fetal sheep liver genomic DNA, were used to prepare a "library" of amplified genomic sequences with the lambda vector Charon 4A and it was demonstrated that these two DNA fragments contain overlapping sequences of the pro alpha 2 gene.

Journal ArticleDOI
TL;DR: The data indicate that the part of the non-transcribed spacer contained in Mr974 consists of at least two structural domains of distinct sequence characteristics, which accounts for the observed instability and length heterogeneity of the rDNA insert in several clones and probably for the heterogeneity in the structure of the ribosomal repeats in the genomic DNA.
Abstract: The DNA of the recombinant phage λgtWES Mr974 (Grummt et al., 1979) which contains the 18S region and adjacent spacer sequences of the ribosomal genes from mouse has been digested with the restriction endonuclease Sall. Fragments corresponding to the non-transcribed spacer (A and D) and the external transcribed spacer (B) have been prepared and their nucleotide composition and sequence organization has been determined. The data indicate that the part of the non-transcribed spacer contained in Mr974 consists of at least two structural domains of distinct sequence characteristics. Fragment A contains 49% G+C and exhibits a high sequence complexity. Fragment D, the spacer fragment flanking the coding region, is very rich in G+C and is obviously composed of an internally repetitive sequence which is cut by several restriction enzymes into a similar set of repetitive fragments. Most of the fragments have sizes that are multiples of 60 and 80 or 140 base pairs, respectively, suggesting an alternating 60/80bp arrangement. This regular sequence in fragment D accounts both for the observed instability and length heterogeneity of the rDNA insert in several clones and probably for the heterogeneity in the structure of the ribosomal repeats in the genomic DNA.

Journal ArticleDOI
TL;DR: Mouse liver poly(A)+mRNA was reverse transcribed using oligo-p(dT) or random oligonucleotides as primers to yield cDNA about equal to the mass of the template RNA to establish for the first time that cDNA represents essentially all of the sequence complexity of a diverse template RNA population in which individual mRNA species are present in vastly different concentrations.
Abstract: Mouse liver poly(A)+mRNA was reverse transcribed using oligo-p(dT) or random oligonucleotides as primers to yield cDNA about equal to the mass of the template RNA. The size profile of the oligo-p(dT)-primedd cDNA was similar to that of the template RNA. RNA or cDNA driven saturation annealing of labeled single copy genomic DNA (scDNA) showed that 2% of the scDNA was complementary in either case indicating the sequence complexity of cDNA was equivalent to that of the template mRNA. These results establish for the first time that cDNA represents essentially all of the sequence complexity of a diverse template RNA population in which individual mRNA species are present in vastly different concentrations. RNA driven hydridization of the cDNA showed that about 40% of the cDNA mass represents most of the sequence complexity of the template RNA. Also, kinetics of this hybridization indicate a complexity of 58,000 kb for the template RNA, a value similar to that obtained by scDNA hybridization. We conclude that appropriately characterized cDNA probes can be used to make valid qualitative and quantitative comparisons of the complex, infrequent class mRNAs of different cells and tissues.

Journal ArticleDOI
TL;DR: The recombinants described contain extensive regions of DNA surrounding the globin genes, making them useful for identifying regulatory sequences as well as determining the sequence organization of the goat Globin genes.