Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.1.26.9 (ribonuclease)
 6,589 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The complete nucleotide sequences of human placenta, human liver, and bovine liver tRNAAsn have been determined. A comparison of these tRNA structures with the previously reported nucleotide sequences of rat liver and Walker 256 carcinosarcoma tRNAAns reveals that the primary nucleotide sequences of the major species of mammalian cytoplasmic tRNAasn are conserved in higher eucaryotes. The complete nucleotide sequence of these tRNAs is: pG-U-C-U-C-U-G-U-m1G-m2G-C-G-C-A-A-D-C-G-G-D-X-A-G-C-G-C-m2(2)G-psi-psi-C-G-G-C-U-Q(G)-U-U-t6A-A-C-C-G-A-A-A-G-m7G-D-U-G-G-U-G-G-Z-psi-C-G-m1A-G-C-C-C-A-C-C-C-A-G-G-G-A-C-G-C-C-AOH where X is 3-(3-amino-3-carboxyl-n-propyl)uridine, Q is 7-(4,5-cis-dihydroxyl-1-cyclopenten-3-yl-aminomethyl)-7-deazaguanosine, Z is an unknown modified nucleotide, and Q(G) represents the replacement of Q nucleoside by G nucleoside in Walker 256 carcinosarcoma tRNAAsn. These primary structures were determined by combined use of the 3H- and 32P-post-labeling techniques. Sequences were compared by tritium nucleoside trialcohol analysis, completed RNAase T1 digestion followed by 3H-labeled fingerprinting on polyethylenimine-impregnated cellulose by two-dimensional thin-layer chromatography (TLC), and polyacrylamide gel electrophoresis of either 5'-32P- and/or 3'-[32P]pCp-labeled tRNA after partial ribonuclease digestions.
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PMID:Structural comparison of human, bovine, rat, and Walker 256 carcinosarcoma asparaginyl-tRNA. 678 75

We used the chemical reagents dimethylsulfate and 4'-aminomethyl-4,5',8-trimethylpsoralen and the enzyme T1 ribonuclease to compare the 5'-end structure of ovalbumin mRNA in situ in purified hen oviduct nuclei and polysomes with that of the isolated mRNA. The qualitative pattern of structure-dependent base modifications and T1 ribonuclease cleavage sites in intranuclear and polysomal ovalbumin mRNAs was found to be nearly identical to those in isolated ovalbumin mRNA. These structural data are consistent with the presence of a trigonal stem-loop structure at the 5'-end of ovalbumin mRNA (hairpin-1) in nuclei and polysomes. Similar results were obtained for a coding region structure (hairpin-3) in intranuclear ovalbumin mRNA. We have recently shown that hairpin-1 positively affects the rate of ovalbumin mRNA translation in vitro and is part of a high affinity binding site for eucaryotic initiation factor-2 (eIF-2). The presence of hairpin-1 in ovalbumin mRNA in both a pretranslation state (nuclei) and active translation state (polysomes) is consistent with its hypothesized biological function as an intracellular initiation signal that facilitates the translation of this mRNA.
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PMID:The 5'-end structure of ovalbumin mRNA in isolated nuclei and polysomes. 797 Dec 81