Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.1.30.1 (S1 nuclease)
 3,660 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Double-stranded cDNA synthesized from delta-crystallin mRNA isolated from lens fiber cells of 15-day-old embryonic chicken was cloned in Escherichia coli chi 1776 in the Pst I site of the plasmid pBR322 by using the oligo(dC) . oligo(dG) joining procedure. Twelve Amps Tetr transformants contained sequences complementary to purified delta-crystallin [32P]cDNA. One of the recombinant clones (p delta Cr-2) had an insert of 1241 +/- 240 base pairs, as judged by R-looping analysis with purified delta-crystallin mRNA. The inserted cDNA represents at least 69% of the delta-crystallin coding sequences. p delta Cr-2 was further characterized by restriction analysis, protection of delta-crystallin [3H]cDNA from digestion by S1 nuclease, and hybrid-mediated arrest of delta-crystallin mRNA translation in vitro. p delta Cr-2 provides an invaluable probe for additional analysis of the primary structure, gene organization, and regulated synthesis of delta-crystallin, the principal protein synthesized during lens differentiation in the chicken embryo.
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PMID:Molecular cloning and partial characterization of delta-crystallin cDNA sequences in a bacterial plasmid. 38 37

Rat genomic clones, which together contain all of the rat genomic gamma-crystallin sequences, have been characterized. Five gamma-crystallin genes are located on a contiguous DNA region, 63 X 10(3) base-pairs long. These genes, named (5') gamma 1-1, gamma 1-2, gamma 2-2 and gamma 3-1 (3'), are all oriented head to tail. A sixth gamma-crystallin gene, named the gamma 4-1 gene, could not be linked to the gamma-crystallin gene cluster with our present set of genomic clones. Mapping experiments using single copy sequences which form the extreme 5' or 3' region of the gene cluster showed that, if the gamma 4-1 gene is located on the same chromosome, then it must be separated from the gene cluster by at least 25 X 10(3) base-pairs of DNA. All gamma-crystallin genes have a similar mosaic structure. They contain a large (0.9 X 10(3) to 1.88 X 10(3) base-pairs) intron in the middle of the gene and are further interrupted close to the 5' end of the gene. The length of the first exon varies from about 40 to about 50 base-pairs. The complementary DNA clone pRL-gamma-3 used in this study is a copy of the transcript of the gamma 3-1 gene, while the second complementary DNA clone, pRL-gamma-2, is most likely a copy of the transcript of the gamma 2-1 gene. It is further shown that rat lens messenger RNA protects fragments from the 3' ends of the four other gamma-crystallin genes against degradation by S1 nuclease, hence all six gamma-crystallin genes present in the rat genome must be transcribed in the lens. Repetitive sequences were found to be present between and around the gamma-crystallin genes. Mapping with cloned repetitive sequences showed that three different repeats, designated A, B and C, occur more than once in the gamma-crystallin gene cluster. Repeat C is also found in the gamma 4-1 region. A repetitive region 3' to the gamma 3-1 gene contains members of all three repeat families.
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PMID:Characterization of the rat gamma-crystallin gene family and its expression in the eye lens. 298 30

The transcription initiation sites of the six rat gamma-crystallin genes were mapped by combining the results of primer extension and S1 nuclease mapping experiments. To obtain more accurate results from the S1 nuclease mapping experiments, intron-deleted clones were constructed by a novel and efficient modification of existing methods involving the use of primer extension products to seal the exons. Four of the six gamma-crystallin genes have multiple transcription start sites. The major and most of the minor transcripts start with an adenosine. Analysis of the 5' flanking sequences of the gamma-crystallin genes shows that the sequence determining the position of the cap site is merely -CA- and that its optimal distance from the first T of the TATA box is 32 base pairs. Our data further suggest that an A to G transition in the first two base pairs of the Goldberg/Hogness box of one the genes does not affect the position of its major cap site. This, together with the fact that most minor transcription start sites are located upstream from the major cap sites, suggests that in the long TATA boxes of the rat gamma-crystallin genes the major RNA polymerase 'trap site' is not directly at the beginning of the TATA sequence.
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PMID:Sequence divergence and selection of cap sites in the rat gamma-crystallin gene family. 301 30

The rat beta B1-crystallin gene is 13.6 kilobases long and contains six exons. The coding region of the gene is divided over five exons. Each functional entity of the protein is encoded by a separate exon except for the carboxyl-terminal extension, which shares the last exon with the fourth protein motif. Exon 2, encoding the amino-terminal extension of the protein, contains two direct repeats with an overall homology of 68% to the rat brain identifier sequence. A copy of the brain identifier sequence is also found in the 3'-flanking region of the gene. The start site of the mRNA was located by S1 nuclease mapping and analysis of the RNA sequence. The 5' end of the gene was shown to be a 27-base-pair noncoding exon, which is separated from the translation start site by 1.36 kilobases of intronic DNA. The 5'-flanking sequence of the beta B1 gene is highly homologous to that of a gamma-crystallin gene.
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PMID:Intron insertions and deletions in the beta/gamma-crystallin gene family: the rat beta B1 gene. 345 46

The eye lens contains a structural protein, alpha crystallin, composed of two homologous primary gene products alpha A2 and alpha B2. In certain rodents, still another alpha crystallin polypeptide, alpha AIns, occurs, which is identical to alpha A2 except that it contains an insertion peptide between residues 63 and 64. In this paper we describe the complete alpha A crystallin gene that has been cloned from DNA isolated from Syrian golden hamster. Evidence is provided that the alpha A gene is present as a single copy in the hamster genome. The detailed organization of the gene has been established by means of DNA sequence analysis and S1 nuclease mapping, revealing that the gene consists of four exons. The first exon contains the information for the 68 base-pair long 5' non-coding region as well as the coding information for the first 63 amino acids. The second exon encodes the 23 amino acid insertion sequence, the third exon codes for amino acid 87 to 127 of the alpha AIns chain, whereas the last exon encodes the C-terminal 69 amino acids and contains the information for the 523 base-pair long 3' non-coding region. The second exon is bordered by a 3' splice junction (A X G/G X C), which deviates from the consensus for donor splice sites (A X G/G X T). This deviation is found in both hamster and mouse. An internal duplication was detected in the first exon by using a DIAGON-generated matrix for comparison. By means of similar DIAGON-generated matrices it was confirmed that the amino acids coded for by the third and fourth exons are homologous to the small heat-shock proteins of Drosophila, Caenorhabditis and soyabean. The implications of the differential splicing and the evolutionary aspects of the detected homologies are discussed.
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PMID:Complete structure of the hamster alpha A crystallin gene. Reflection of an evolutionary history by means of exon shuffling. 405 47

The eye lens contains a structural protein (alpha-crystallin) composed of two homologous primary gene products, alpha A2 and alpha B2. In certain rodents, there is another alpha-crystallin polypeptide, alpha Ains which is identical with alpha A2 except that it contains an additional peptide between residues 63 and 64 of the alpha A2 chain. The alpha A-crystallin gene encodes the alpha Ains peptide in a separate 69-base pair exon, suggesting that the alpha A2 and alpha Ains mRNAs are derived by alternative RNA splicing. In the present study, we report the isolation of a cloned cDNA (pM alpha AinsCr1) from a cDNA library constructed in the bacterial plasmid pBR322. The nucleotide sequence of pM alpha AinsCr1 in the region of the insert peptide provides compelling evidence that the alpha Ains mRNA is derived from the same gene as the alpha A2 mRNA. S1 nuclease protection experiments, using a DNA fragment from pM alpha AinsCr1, showed that the alternative splicing gives 5 to 10 times more alpha A2 than alpha Ains mRNA. This ratio is comparable to that of the respective polypeptides in the lens. We did not detect an age-related or a differentiation-related difference in the ratio of the alpha A2 to the alpha Ains mRNA or their polypeptides. These results indicate that when the alpha A-crystallin gene is expressed in the lens, it splices the RNA sequences from the insert exon into functional mRNA 10 to 20% of the time.
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PMID:Alternative splicing of alpha A-crystallin RNA. Structural and quantitative analyses of the mRNAs for the alpha A2- and alpha Ains-crystallin polypeptides. 654 84

The soybean possesses a gene family encoding the major low mol. wt. heat-shock proteins of 15-18 kd. We have determined the primary DNA sequences of two of the genes, both located on the same subgenomic DNA fragment. The protein coding regions are characterized by long uninterrupted open reading frames and by sequence homology of 92% and 100% with a heat-shock specific cDNA. One protein sequence deduced from the completely cloned gene hs6871 is composed of 153 amino acids with a total mol. wt. of 17.3 kd; the other protein is a truncated polypeptide containing 73 amino acids at the carboxy-terminal end of an incompletely cloned heat-shock gene designated hs6834. Investigations of the hydrophilic/hydrophobic characteristics of the polypeptides revealed a conservation of structural features between heat-shock proteins from soybean, Caenorhabditis and Drosophila and mammalian lens alpha-crystallin. The 5' end of the soybean heat-shock gene hs6871 was mapped by S1 nuclease at a position which is 100 nucleotides upstream from the translation start codon and 25 nucleotides downstream from a TATA-box sequence. Six other potential promoter elements which are homologous to the Drosophila heat-shock consensus sequence CT-GAA-TTC-AG-, are present within 150 nucleotides upstream from the TATA-box. The possible functions of these promoter elements in transcriptional regulation of expression of soybean heat-shock gene are discussed.
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PMID:The DNA sequence analysis of soybean heat-shock genes and identification of possible regulatory promoter elements. 1645 63