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)

A Urechis caupo histone gene tandem repeat has been isolated from a 5.0-kilobase EcoRI genomic library in lambda gtWES.lambda B. Genomic reconstruction experiments indicate that the cloned sequence is repeated approximately 100 times per haploid genome. Unique restriction fragments from the cloned sequence hybridize with individual core histone genes from a histone gene tandem repeat of the sea urchin, Strongylocentrotus purpuratus. No hybridization is detected when restriction digests are probed with a sea urchin H1 histone gene. Hybrid selection and in vitro translation of embryo mRNAs demonstrate that the clone contains sequences complementary to all four core histones; however, no H1 histone is detected among the translation products. Based on a restriction site map of the clone and the subcloned sequences which hybridize to the histone mRNAs, the order of the core histone genes in the clone is shown to be H3 H2A H2B H4. S1 nuclease hybrid protection mapping is used to locate the coding regions and to determine the transcript lengths of the core histone mRNAs. The transcript lengths of H2A, H2B, H3, and H4 mRNAs are approximately 464, 438, 494, and 397 bases, respectively. The S1 nuclease mapping also demonstrates that H2A and H4 are transcribed from one DNA strand while H2B and H3 are transcribed from the other strand. In the tandem repeat, the genes are organized so that transcription of the H2A-H2B and H3-H4 gene pairs is divergent.
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PMID:Cloning and characterization of a core histone gene tandem repeat in Urechis caupo. 284 32

The human H1 histone gene FNC16 resides in a 2.7-kb EcoRI fragment present in a histone gene cluster that also contains one copy of each of the core (H2A, H2B, H3, and H4) histone genes. The cap site for FNC16 H1 mRNA is located 58 nucleotides upstream of the ATG translational start codon, and S1 nuclease protection analysis clearly distinguishes between correctly initiated FNC16 transcripts and transcripts from other nonidentical H1 histone genes. We have observed, using S1 analysis, that the FNC16 H1 histone gene is expressed in a replication-dependent manner in HeLa cells and is expressed in proliferating, but down-regulated in differentiated, HL60 cells. Similar results were found in HeLa S3 and HL60 cells for the cell cycle-dependent human H4 histone gene FO108. Nuclear extracts derived from HeLa S3 cells are capable of directing FNC16 H1 histone gene transcription in vitro. This finding is consistent with previous work that established at least two sites for protein-DNA interaction in vitro in the proximal promoter region of this gene. We have observed a difference in the extent to which the FNC16 H1 histone gene is expressed in HeLa S3 and proliferating HL60 cells, which suggests that this H1 gene is differentially regulated in various cell types. Although results reported for a potentially identical human H1 histone gene designated Hh8C (LaBella, F., Zhong, R., and Heintz, N. (1988) J. Biol. Chem. 263, 2115-2118) support differential regulation of human H1 genes in various cell types, their observations that the Hh8C gene is not expressed in HeLa cells and that the restriction patterns differ indicate that FNC16 and Hh8C are different H1 genes.
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PMID:The human H1 histone gene FNC16 is functionally expressed in proliferating HeLa S3 cells and is down-regulated during terminal differentiation in HL60 cells. 318 72

The histone H2A gene of the filamentous fungus Aspergillus nidulans has been cloned and sequenced. There is a single H2A gene in the genome of A. nidulans, and it contains three introns. The introns are 51 nucleotides (nt), 56 nt and 50 nt in length and split codons for amino acids (aa) 18, 48 and 116 of the predicted protein. The transcriptional start and termination points have been determined using an S1 nuclease protection assay. The predicted protein is 132 aa residues in length and surprisingly has a threonine after the initiator methionine instead of the usual serine. The sequence of the predicted histone H2A protein is compared to histone H2A proteins from Schizosaccharomyces pombe, Saccharomyces cerevisiae and calf thymus. Comparison of the amino acid sequence to these other H2A proteins shows that the divergence of amino acid sequences between H2A proteins is found in two clustered sites.
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PMID:The unique histone H2A gene of Aspergillus nidulans contains three introns. 331 84

We describe the isolation and initial characterization of seven independent lambda Charon 4A recombinant phages which contain human histone genomic sequences (designated lambda HHG). Restriction maps of these clones and localization of the genes coding for histones H2A, H2B, H3, and H4 are presented. The presence of histone encoding regions in the lambda HHG clones was demonstrated by several independent criteria including hybridization with specific DNA probes, hybrid selection/in vitro translation, and hybridization of lambda HHG DNAs to reserve Southern blots containing cytoplasmic RNAs from G1-, S-, and arabinofuranosylcytosine (cytosine arabinoside)-treated S-phase cells. In addition, the lambda HHG DNAs were shown to protect in vivo labeled H4 mRNAs from S1 nuclease digestion. Based on the analysis of the lambda HHG clones, human histone genes appear to be clustered in the genome. However, gene clusters do not seem to be present in identical tandem repeats. The lambda HHG clones described in this report fall into at least three distinct types of arrangement. One of these arrangements contains two coding regions for each of the histones H3 and H4. The arrangement of histone genes in the human genome, therefore, appears to be different from that in the sea urchin and Drosophila genomes in which each of the five histone-encoding regions (H1, H2A, H2B, H3, and H4) is present only once in each tandemly repeated cluster. At least one clone, lambda HHG 41, contains, in addition to the histone genes, a region that hybridizes with a cytoplasmic RNA approximately 330 nucleotides in length. This RNA is not similar in size to known histone-encoding RNAs and is present in the cytoplasm of HeLa cells predominantly in the G1 phase of the cell cycle.
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PMID:Organization of human histone genes. 628 86

Sea urchin (psammechinus miliaris) H2A histone genes shown to be promoter mutants from oocyte injection experiments were tested for their ability to initiate transcription in vitro. Circular templates were transcribed with HeLa cell extracts, and the transcripts were assayed by mung bean or S1 nuclease mapping of the 5' ends. The transcripts of the H2A mutants produced in vitro were qualitatively similar and, in most cases, identical to those seen in oocyte injection experiments, but quite large quantitative differences were observed for some H2A mutant genes. Both the T-A-T-A box and far upstream sequences residing in the modulator segment E [Grosschedl, R. & Birnstiel, M. L. (1980) Proc. Natl. Acad. Sci. USA 77, 7102--7106] were found to be essential for maximal transcription in vitro. Deletion of either of these sequence elements reduced transcription to 20%. A similar reduction in the amount of H2a transcripts was found when a T-A-T-A-to-T-A-G-A point mutant was tested in vitro. Essential far upstream sequences were mapped between nucleotides -139 and -111, 5' to the initiation site of transcription. In the standard run-off transcription test using restriction fragments, the effects of these sequences could be mimicked by free DNA ends, suggesting that the function of this in vitro upstream sequence might be to provide an entry side for RNA polymerase II.
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PMID:Delimitation of far upstream sequences required for maximal in vitro transcription of an H2A histone gene. 695 85