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

We have isolated and sequenced the 5' proximal exons and flanking regions of the chicken very low density apolipoprotein II (apo-VLDLII) and serum albumin genes. These genes specify the most abundant mRNA species present in livers of hens or estrogen-treated roosters. Sequencing revealed that the promoter region of the estrogen-dependent apo-VLDLII gene contained at least two potential transcriptional initiation sites, preceded by appropriately positioned "ATA" sequences. One is homologous with the cap site of the ovalbumin gene, and the other exhibits a match of 10 out of 12 nucleotides with the cap site of the serum albumin gene. S1 nuclease mapping indicates that both sites are active in vivo, although the "ovalbumin"-like site is by far the most efficient at all stages of the estrogenic response. The relative efficiencies of these two sites are maintained during in vitro transcription of truncated templates. A third site, that was not anticipated from sequencing data, is active in vivo but inactive in vitro. A conserved 5' flanking element, initially identified during studies on egg white protein genes, is also present upstream from the apo-VLDLII and serum albumin genes. Its removal does not affect initiation site selection in vitro. Regions of the apo-VLDLII and ovalbumin genes extending 100 nucleotides downstream from the "TATA box" contain several striking homologies that suggest a common mode of evolution.
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PMID:The 5' noncoding and flanking regions of the avian very low density apolipoprotein II and serum albumin genes. Homologies with the egg white protein genes. 618 37

Analbuminemic rats, which lack serum albumin, were previously found to have no albumin mRNA in the cytoplasm of the liver. In the present study, the existence of nuclear albumin mRNA precursors in the liver of analbuminemic rats was examined by RNA X cDNA hybridization kinetics. Albumin mRNA precursors were present in the nuclei of analbuminemic rat liver at almost normal levels, despite the absence of albumin mRNA from the cytoplasm. Nuclear RNA of analbuminemic rat liver was subjected to electrophoresis on 1% agarose gel in parallel with nuclear RNA of normal rat liver. RNA was transferred from the gel to diazobenzyloxymethyl-paper and hybridized to cloned cDNA. Several bands of putative albumin mRNA precursors were obtained with nuclear RNA of analbuminemic rat liver and some of them were indistinguishable from those of normal rat liver. Nuclear RNA of analbuminemic rats was hybridized to 3'-end-labeled cloned cDNA under the conditions of RNA excess and then digested completely with S1 nuclease and subjected to electrophoresis on polyacrylamide gel. By this technique, nuclear RNA that could hybridized to cDNA was found to have the albumin mRNA sequence in at least the 3' half of the mRNa that was covered by cloned cDNA. For comparison of the structures of the albumin genes of analbuminemic and normal rats, DNAs from rat livers of both types were digested completely with EcoRI, HindIII, and Pst I; the fragments were separated by electrophoresis on 1% agarose gel, transferred to nitrocellulose paper, and hybridized to cloned cDNA. The intensities of the corresponding bands and the digestion patterns of the analbuminemic and normal rat genes were indistinguishable. From these data, it is concluded that analbuminemic rats have a unique type of mutation(s) affecting albumin mRNA maturation.
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PMID:Presence of albumin mRNA precursors in nuclei of analbuminemic rat liver lacking cytoplasmic albumin mRNA. 695 Apr 24