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At least 37 records · Page 2Linked to original sources
PubMed1977

Sequences homologous to ribosomal insertions occur in the Drosophila genome outside the nucleolus organizer.

Many repeating units of Drosophila melanogaster rDNA contain a DNA sequence within the gene for 28S rRNA that does not code for rRNA. This sequence has been called the ribosomal insertion [Wellauer, P. K. & Dawid, I. B. (1977) Cell 10, 193-212]. We report here that members of the same sequence family occur outside the ribosomal locus. "Non-rDNA insertion DNA" was separated from rDNA by density gradient centrifugation, and sequences homologous to the ribosomal insertion were detected by hybridization with restriction endonuclease fragments derived from a cloned rDNA repeating unit. Pure insertion sequences from cloned rDNA separated from main band DNA and behaved like a component with high G + C content. Non-rDNA components hybridizing to the insertion also separated from main band DNA but less so than pure insertion sequences, suggesting that non-rDNA insertion sequences are linked to DNA of different nucleotide composition. Restriction endonuclease analysis of non-rDNA insertion DNA showed many fragments of different sizes. The patterns obtained were similar in embryonic, larval, pupal, and adult DNA and DNA from cultured cells (Schneider cell line 3). Non-rDNA insertion sequences account for about 0.2% of the genome or about 400 kbases of DNA per haploid complement.

Animals↗
PubMed1979

The isolation and partial sequence of peptides produced by cyanogen bromide cleavage of calf thymus non-histone chromosomal high-mobility-group protein 2. Sequence homology with non-histone chromosomal high-mobility-group protein 1.

Peptides produced by CNBr cleavage of non-histone chromosomal protein HMG 2 (CNBr peptides) were isolated and characterized, and their partial sequences were determined. The present sequence data account for over half of the sequence of the protein HMG (high-mobility-group) 2 molecule, and, together with previously published results, provide interesting information on the charge distribution within the molecule. Comparison of the CNBr-peptide-sequence data for protein HMG 2 with the previously published data on the CNBr peptides from protein HMG 1 reveals extensive sequence homology between the two proteins. Detailed evidence for the amino acid-sequence data has been deposited as Supplementary Publication SUP 50095 (6 pages) at the British Library Lending Division, Boston Spa, Wetherby, West Yorkshire LS23 7BQ, U.K., from whom copies may be obtained on the terms given in Biochem. J. (1978) 169, 5.

Amino Acid Sequence↗
PubMed1978

Nucleotide sequence homology at the 3' termini of RNA from vesicular stomatitis virus and its defective interfering particles.

Vesicular stomatitis virus (VSV) and defective interfering (DI) particle RNAs were labeled at their 3' ends by using RNA ligase and cytidine 3',5'-bis[32P]phosphate. The RNAs were subjected to partial digestion with alkali and analyzed by oligonucleotide fingerprinting in two dimensions. VSV and DI particle RNAs have complete sequence homology for the first eight bases from the 3' end. The following four positions contain three mismatched nucleotides in which guanosine residues in one strand are replaced by uridine residues in the other. There is again complete homology for the next five bases (positions 13-17). The locations of purine residues within the sequence were confirmed by partial digestion with RNase T1 and RNase U2 and separation by size on 20% acrylamide gels. The latter method also indicated that sequences of VSV and DI particle RNAs diverge beyond the 18th nucleotide from the 3' termini.

Base Sequence↗
PubMed1979

Lack of sequence homology between the nucleic acids of Rauscher leukaemia virus and polyoma virus Y8e produced simultaneously in a continuous mouse cell line.

In a continuous cell line (Y8e) from spleen and thymus cells of mice, infected with RLV, the presence of both RLV and polyoma virus Y8e in a single cell could be demonstrated by electron microscopy. A comparison of the nucleic acids of RLV and polyoma virus from Y8e cells by two molecular hybridization methods showed lack of sequence homology between the viral nucleic acids.

Animals↗
PubMed1978

Intracellular serine protease of Bacillus subtilis: sequence homology with extracellular subtilisins.

Intracellular serine protease was isolated from stationary-grown Bacillus subtilis A-50 cells and purified to homogeneity. The molecular weight of the enzyme is 31,000 +/- 1,000, with an isoelectric point of 4.3. Its amino acid composition is characteristically enriched in glutamic acid content, differing from that of extra-cellular subtilisins. The enzyme is completely inhibited with phenylmethylsulfonyl fluoride and ethylenediaminetetraacetic acid. Intracellular protease possesses negligible activity towards bovine serum albumin and hemoglobin, but has 5- to 20-fold higher specific activity against p-nitroanilides of benzyloxycarbonyl tripeptides than subtilisin BPN'. Esterolytic activity of the enzyme is also higher than that of subtilisin BPN'. The enzyme is sequence homologous with secretory subtilisins throughout 50 determined NH2-terminal residues, indicating the presence of duplicated structural genes for serine proteases in the B. subtilis genome. The occurrence of two homologous genes in the cell might accelerate the evolution of serine protease not only by the loosening of selective constrainst, but also by creation of sequence variants by means of intragenic recombination. Three molecular forms of intracellular protease were found, two of them with NH2-terminal glutamic acid and one minor form, three residues longer, with asparagine as NH2 terminus. These data indicate the possible presence of an enzyme precursor proteolytically modified during cell growth.

Amino Acid Sequence↗
PubMed1976

Sequence homology between Moloney murine sarcoma virus and Moloney leukemia virus RNA.

The Moloney murine sarcoma-leukemia virus [M-MSV (MuLV)], propagated at high multiplicity of infection (MOI), was demonstrated previously to contain a native genome mass of 4 X 10(6) daltons as contrasted to a mass of 7 X 10(6) daltons for Moloney murine leukemia virus (M-MuLV). The 4 X 10(6)-dalton classof RNA from M-MSV (MuLV) was examined for base sequence homology with DNA complementary to the 7 X 10(6)-dalton M-MuLV RNA genome. Approximately 86% of the M-MSV (MuLV) was protected from RNase digestion by hybridization, whereas 95% of M-MuLV was protected under identical conditions. These results indicate that the small RNA class of high-MOI M-MSV (MuLV) contains little (perhaps 10%) genetic information not present in M-MuLV. Virtually all of the 1.8 X 10(6)-dalton subunits of M-MSV (MuLV) RNA contained regions of poly(A) since 94% of the RNA bound to oligo(dT) cellulose in 0.5 M KCl. This suggests that the formation of the 1.8 X 10(6)-dalton subunits occurs before their packaging into virions and does not result from hydrolysis of intact 3.5 X 10(6)-dalton subunits by a virion-associated nuclease.

Base Sequence↗
PubMed1977

Amino acid sequence homology and the vitamin K-dependent proteins.

Examination of amino acid sequence data on bovine vitamin K-dependent clotting zymogens, using the Gibbs and McIntyre diagonal plot, leads to the conclusion that they are homologous and have evolved by a series of gene duplications. Plasminogen is also homologous but lacks the region containing glutamic acid (Glu) residues gamma-carboxylated in a vitamin K-dependent step. Both prothrombin and plasminogen show internal sequence homology resulting from partial gene duplication and quintuplication respectively; each internal homology loop in prothrombin shows significant homology with each of the five putative loops in plasminogen. Recently, Walz et al. (Proc. natn. Acad. Sci. USA 74: 1969-1972, 1977) have sequenced the non-thrombin region of human prothrombin (residues 1-273) and this has enabled identification of regions conserved in 90 million years of eutherian evolution. The relative conservatism of homology loop 1 (bovine residues 66-144) which has no known function is discussed 'gamma-Carboxyglutamic acid; (Gla) has been found in proteins unrelated to the plasma clotting factors; a bovine bone-matrix protein('osteocalcin') has been sequenced by Price et al. (Proc. natn. Acad Sci. USA 73: 3373-3375, 1976) but it shows no homology with prothrombin or factor X.

Amino Acid Sequence↗
PubMed1979

Amino acid sequence homology between histone H5 and murine leukemia virus phosphoprotein p12.

The amino terminal acid sequences of several mouse leukemia virus phosphoproteins (p12) show definite homology with the amino terminal conserved region of H5 histones, the phosphorylated nuclear proteins of nucleated erythrocytes. Differences in the amino acid compositions of the two groups of proteins seem to rule out the possibility that they evolved from a single common ancestral gene. The finding of sequence homology between viral p12's and cellular histones, however, is consistent with evolution of retrovirus structural proteins by a process of differentiation from preexisting cellular genes. The conserved primary and secondary structure at the amino terminal region, common to both groups of proteins, may be related to their common function of nucleic acid binding modulated by phosphorylation.

Amino Acid Sequence↗
PubMed1979

Sequence homologies of (guanosine + cytidine)-rich regions of mitochondrial DNA of Saccharomyces cerevisiae.

The nucleotide sequences of two distinct regions of mitochrondrial DNA of Saccharomyces cerevisiae are reported. The regions studied have a high content of G + C (45%) and contain closely spaced Hpa II and Hae III restriction sites. Both regions have sequences that are homologous over a lenght of 47 base-pairs. In addition, the two regions are highly palindromic. These data support certain aspects of the organization of mitochondrial DNA proposed by Prunell and Bernardi (Prunell, A., and Bernardi, G. (1977) J. Mol. Biol. 110, 53--74).

Base Sequence↗
PubMed1979

Structure of the 3' hairpin termini of four rodent parvovirus genomes: nucleotide sequence homology at origins of DNA replication.

The nucleotide sequences of the 3' termini of the DNA from four autonomous rodent parvoviruses have been determined. The terminus of each genome exists as a Y-shaped hairpin structure involving 115 or 116 nucleotides. The sequence of this region of DNA is highly conserved and shows no evidence of internal sequence heterogeneity, a characteristic which is observed in the terminal nucleotide sequence of the helper-dependent, adeno-associated viruses (Berns et al., 1978a). The implications of these results with respect to the models of parvovirus DNA replication are discussed.

Base Sequence↗
PubMed1979

Sequence homology adjacent to the 3' terminal poly(A) of cowpea mosaic virus RNAs.

We have determined the sequence of 80 nucleotides adjacent to 3' poly(A) of both (middle and bottom component) cowpea mosaic virus RNAs, using dideoxynucleotide termination of reverse transcription. Sequence conservation is indicated, there being about 80% homology between the first 65 bases of each RNA. Although both RNAs are polyadenylated, there is no AAUAAA sequence as associated with most known polyadenylated mRNAs of eukaryotes and viruses. However both RNAs are U and A-rich in this region.

Avian Myeloblastosis Virus↗
PubMed1979

Extensive sequence homology at the 3'-termini of the four RNAs of cucumber mosaic virus.

The sequences of 270 residues from the 3'-termini of the four RNAs of cucumber mosaic virus have been determined by copying the in vitro polyadenylated RNAs with reverse transcriptase using d(pT8G) as primer and the 2',3'-dideoxynucleoside 5'-triphosphates as specific chain terminators. The terminal sequences of RNAs 3 and 4 were identical; this was expected since hybridization data has shown that the sequence of RNA 4 was present at the 3'-end of RNA 3 (Gould and Symons (1978) Eur. J. Biochem. 91, 269-278). The first 138 residues of RNAs 1 and 2 were identical to those of RNAs 3 and 4 except for one residue in RNA 1 and three residues in RNA 2. From residue 139 to 270 from the 3'-terminus, RNAs 1 and 2 showed, relative to RNAs 3 and 4, a non-homologous region of 33 residues, a homologous region of 40 residues, a partially homologous region of 14 residues which probably extended to about residue 300. There were 11 residues different between RNAs 1 and 2.

Base Composition↗