Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.7.7.49 (reverse transcriptase)
 31,746 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A 15 kb region of the 100 kb mitochondrial genome of Podospora anserina has been mapped and sequenced (1 kb = 10(3) base-pairs). The genes for ND4L and ND5 are identified as contiguous genes with overlapping termination and initiation codons. In race A (101 kb) the gene for ND4L (4.3 kb) has a gene duplication within an intron including a second subgroup IC intron. Race s (95 kb) lacks this second gene complex. Each intron has the identical 5' exon boundary. Secondary structure analysis showed that the closest relative of the second intron is the first intron itself. The open reading frames of the two introns are also closely related to each other as well as to their counterpart in the ND4L gene of Neurospora crassa. The 9.9 kb ND5 gene starts immediately at the termination codon of ND4L and is split by two group IB introns, one group IC intron and one group II intron. The group II intron is closely related to other group II introns although its open reading frame sequence similarity with retroviral reverse transcriptase appears to be more divergent. The similarities in secondary structure and open reading frames for these six introns are discussed.
J Mol Biol 1990 Mar 20
PMID:DNA sequence analysis of the mitochondrial ND4L-ND5 gene complex from Podospora anserina. Duplication of the ND4L gene within its intron. 231 2

Porcine prolactin cDNA clones were screened using antiserum against ovine prolactin from a cDNA library of porcine anterior pituitary, and their nucleotide sequences were determined by the chain-termination method. The nucleotide sequence of the 5' untranslated region and part of the signal peptide region were determined by direct RNA sequencing with reverse transcriptase. The composite sequence of 957 nucleotides showed a signal sequence of 30 amino acids and a further 199 amino acids corresponding to the mature prolactin molecule. The predicted sequence confirmed the amino acid sequence determined previously by direct protein analysis, except for one amide form at residue 122 (Gln instead of the reported Glu). Northern blot analysis showed that the length of the porcine prolactin mRNA was about 1.1 kb. The porcine prolactin amino acid sequence showed 81, 80, 64, 62, 80 and 31% homology with human, bovine, rat, mouse, chick and salmon forms respectively. The identical amino acid residues showed marked clustering in four domains, two of which are highly conserved throughout a wide range of species. The hydropathy and secondary structure of porcine prolactin were analysed and compared with those of porcine GH, which shares the same ancestral gene. The two highly conserved regions of both hormones showed similar hydrophilicity, and the predicted secondary structures indicated that these regions in each hormone form different structures with differences in extension of the hydrophilic residues outside the molecule.
J Mol Endocrinol 1990 Apr
PMID:Molecular cloning of cDNA for porcine prolactin precursor. 234 90

Individual mRNA coding for proteins of the alpha-polymerase complex were isolated from replicating hepatocytes. cDNAs were synthesized by reverse transcriptase. Three clones were identified by colony hybridization of the S period cDNA library. The sequences of these clones were complementary to the investigated mRNAs. Two clones named pr12 and pr167 revealed increased expressions in the S period. The level of mRNA pr127 does not change during liver regeneration. The amount of pr127 mRNA was about 1% of the total mRNA population. pr12, pr127 and pr167 mRNAs were isolated by the hybrid-selection method and were translated in a cell-free system. The products of translation were analysed by "activity" gel. It was shown that pr167 mRNA coded for protein 140 kDa with DNA polymerase activity. pr12 protein is an unknown component of the alpha-polymerase complex. We suggested that this protein participates in the initiation of DNA replication.
Mol Biol (Mosk)
PMID:[Increased expression of genes coding for replication proteins during the period of DNA synthesis]. 240 40

Plasmids were constructed in which a HindIII fragment of rDNA (6.4 x 10(3) base-pairs) was inserted into vectors pGEM-1 and 2 in both orientations. The DNA insert encoded the yeast 35 S precursor rRNA beginning 180 bases upstream from the 5' end of the mature 18 S rRNA and ending 289 bases beyond the 3' end of the mature 25 S rRNA. The precursor rRNA molecules produced in vitro consisted of 6430 nucleotides, with about 15 residues derived from the Gemini vector on both ends. The general extent of secondary structure of the precursor rRNA was examined by ethidium fluorescence and compared to that of the mature rRNAs. Both precursor and mature rRNAs responded similarly to changes in magnesium ion concentration and to digestion by cobra venom and T1 ribonucleases. The higher-order structure of the internal transcribed spacer-1 (ITS-1) region of the 35 S rRNA molecule was further examined by kethoxal and dimethylsulfate modifications and primer extension. Accessible adenine and guanine residues were located by primer extension analysis with avian myeloblastosis virus reverse transcriptase. On the basis of experimental data and computer-generated structures, a secondary structure model was proposed for the ITS-1 region. In this model, six hairpin stems involving adjacent nucleotides are present. A long-range interaction between nucleotides at the middle of the ITS-1 region and an, as yet, unidentified sequence located at another region of the precursor rRNA is suggested also. A candidate for this interacting sequence is that previously proposed, on a theoretical basis, to be involved in the removal of the precursor 18 S rRNA species for 35 S precursor molecule.
J Mol Biol 1990 Jan 20
PMID:Yeast precursor ribosomal RNA. Molecular cloning and probing the higher-order structure of the internal transcribed spacer I by kethoxal and dimethylsulfate modification. 240 50

We have determined the complete nucleotide sequence of the copia element present at the white-apricot allele of the white locus in Drosophila melanogaster. This transposable element is 5,146 nucleotides long and contains a single long open reading frame of 4,227 nucleotides. Analysis of the coding potential of the large open reading frame, which appears to encode a polyprotein, revealed weak homology to a number of retroviral proteins, including a protease, nucleic acid-binding protein, and reverse transcriptase. Better homology existed between another part of the copia open reading frame and a region of the retroviral pol gene recently shown to be distinct from reverse transcriptase and required for the integration of circular DNA forms of the retroviral genome to form proviruses. Comparison of the copia sequence with those of the Saccharomyces cerevisiae transposable element Ty, several vertebrate retroviruses, and the D. melanogaster copia-like element 17.6 showed that Ty was most similar to copia, sharing amino acid sequence homology and organizational features not found in the other genetic elements.
Mol Cell Biol 1985 Jul
PMID:Complete nucleotide sequence of the Drosophila transposable element copia: homology between copia and retroviral proteins. 241 Jul 72

By genetic analysis, we have localized a new mutation, isolated from rho-crp background, responsible for a carbohydrate-positive phenotype. The mutation maps in the rpoB gene coding for the beta-subunit of Escherichia coli RNA polymerase. Using reverse transcriptase analysis of transcripts obtained in vivo and transcription assays in vitro, we have shown that this altered RNA polymerase can efficiently initiate the transcription of the lactose operon in the absence of the cAMP-CRP complex both in vivo and in vitro.
J Mol Biol 1985 Dec 05
PMID:RNA polymerase mutant able to express in vivo and in vitro the lactose operon in the absence of the cAMP-CRP complex. 241 69

We have investigated in detail the higher-order structure of 16 S ribosomal RNA, both in its naked form and in 30 S ribosomal subunits. Each base in the 16 S rRNA chain has been probed using kethoxal (which reacts with guanine at N1 and N2), dimethylsulfate (which reacts with adenine at N1 and cytosine at N3) and 1-cyclohexyl-3-(2-morpholinoethyl)-carbodiimide metho-p-toluenesulfonate (which reacts with uracil at N3 and guanine at N1). The sites of reaction were identified by primer extension with reverse transcriptase using synthetic oligodeoxynucleotide primers. These results provide a detailed and rigorous experimental test of a model for 16 S rRNA secondary structure, which was derived mainly from comparative sequence analysis. Our data also provide information relevant to tertiary and quaternary structure of 16 S rRNA. Data obtained with naked 16 S rRNA show reasonably close agreement with the proposed model, and data obtained with 30 S subunits show nearly complete agreement. Apart from an apparent overall "tightening" of the structure (in which many weakly reactive bases become unreactive), assembly of the proteins with 16 S rRNA to form 30 S subunits brings about numerous local structural rearrangements, resulting in specific enhancements as well as protections. In many instances, the ribosomal proteins appear to "tune" the 16 S rRNA structure to bring it into accordance with the phylogenetically predicted model, even though the RNA on its own often seems to prefer a different structure in certain regions of the molecule. Extensive protection of conserved, unpaired adenines upon formation of 30 S subunits suggests that they play a special role in the assembly process, possibly providing signals for protein recognition.
J Mol Biol 1986 Feb 05
PMID:Rapid chemical probing of conformation in 16 S ribosomal RNA and 30 S ribosomal subunits using primer extension. 242 86

Total cellular Poly A+ RNA from TEPC15 myeloma and murine lymphoid tissues was analyzed by denaturing agarose gel electrophoresis and Northern blot hybridization to specific heavy chain constant region cDNAs; mu, gamma 2b and alpha RNA species were identified in each of the tissues and in the IgA producing TEPC15 myeloma. In total Poly A+ RNA from TEPC15 myeloma, alpha-cDNA hybridized predominantly to a 2.3 kb RNA species; 11.5 and 4.1 kb RNA species were evident as well. Successive hybridization of the same RNA to mu- and gamma 2b-specific cDNAs demonstrated the presence of both mu and gamma 2b specific RNA species with electrophoretic mobilities apparently identical to the 11.5 and 2.3 kb RNA species identified by alpha-specific hybridization. These data establish the presence of Poly A+ RNA species containing alpha, mu, and gamma 2b sequences in TEPC15 cells and suggest the transcription of RNA from both CH-containing chromosomes in TEPC15 myeloma (one chromosome in the TEPC15 cell line contains all the CH genes while the other chromosome has deleted all CH genes except alpha). In total Poly A+ RNA from normal mouse tissues (Peyer's patch and spleen) all three cDNA probes hybridized predominantly to an 11.5 kb RNA species. Primer extension experiments demonstrated that alpha cDNA could prime for the synthesis by reverse transcriptase of gamma 2b DNA when Peyer's patch Poly A+ RNA was used as the template. This suggests the existence of a single transcript containing alpha and gamma 2b sequences. Murine lymphoid tissues contained putative mRNAs for mu, gamma 2b and alpha heavy chain proteins, whereas TEPC15 myeloma polysomal Poly A+ RNA contained only alpha mRNA.
Mol Immunol 1986 Jun
PMID:Identification of the major immunoglobulin heavy chain poly A+ RNA in murine lymphoid tissue. 242 42

An attempt to study the functional role of one of the most conservative domains found in all RNA-dependent RNA and DNA polymerases of plant and animal viruses (the so called "DD-domain") was made. A structure similar to the "DD-domain" was found in a minor T7 phage tail protein--gpII. Antibodies against this phage protein have been raised and used to probe "DD-domain" in molecules of avian myeloblastose virus reverse transcriptase and E. coli RNA-dependent RNA polymerase. The antibodies are shown to inhibit the activity of these enzymes under certain conditions. At the same time inhibition of the reverse transcriptase reaction causes the decrease in length of the most high molecular cDNA-products as well. The experimental data obtained are discussed in view of the suggested hypothesis on the probable functional role of the "DD-domain" of RNA-dependent polymerases.
Mol Biol (Mosk)
PMID:[Possible functional role of the DD-domain of RNA-dependent polymerases]. 243 38

Earlier studies had shown that a large portion of bacterial messenger RNA carries 3'-terminal polyadenylate sequences, albeit of somewhat shorter length than those associated with eukaryotic mRNA. In this paper, we show for the first time that a specific prokaryotic mRNA is polyadenylated. Three independent lines of evidence demonstrate that a 3'-terminal polyadenylate sequence 10 to 15 nucleotides in length is associated with about 40% of the mRNA of the outer membrane lipoprotein of Escherichia coli: 40% of lipoprotein mRNA binds to oligodeoxythymidylate-substituted cellulose at high ionic strength and is eluted by water; treatment of lipoprotein mRNA with oligodeoxythymidylate and ribonuclease H destroys its ability to bind to oligodeoxythymidylate-cellulose; and in the presence of oligodeoxythymidylate, lipoprotein mRNA can serve as template for the synthesis of DNA complementary to lipoprotein mRNA by reverse transcriptase. In view of the fact that the lpp gene and its downstream-flanking region contain no continuous deoxyadenylate sequences longer than five nucleotides, the polyadenylate moiety must be added post-transcriptionally. It was possible to demonstrate the synthesis of polyadenylated lipoprotein mRNA in toluene-permeabilized cells of E. coli, opening the way for the study of its biosynthesis.
J Mol Biol 1987 Feb 05
PMID:Messenger ribonucleic acid for the lipoprotein of the Escherichia coli outer membrane is polyadenylated. 243 23


<< Previous 1 2 3 4 5 6 7 8 9 10