Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.1.27.5 (RNase)
 17,967 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Prior sequence analysis studies have suggested that bacterial ribonuclease (RNase) Ds comprise a complete domain that is found also in Homo sapiens polymyositis-scleroderma overlap syndrome 100 kDa autoantigen and Werner syndrome protein. This RNase D 3'-->5' exoribonuclease domain was predicted to have a structure and mechanism of action similar to the 3'-->5' exodeoxyibonuclease (proofreading) domain of DNA polymerases. Here, hidden Markov model (HMM) and phylogenetic studies have been used to identify and characterise other sequences that may possess this exonuclease domain. Results indicate that it is also present in the RNase T family; Borrelia burgdorferi P93 protein, an immunodominant antigen in Lyme disease; bacteriophage T4 dexA and Escherichia coli exonuclease I, processive 3'-->5' exodeoxyribonucleases that degrade single-stranded DNA; Bacillus subtilis dinG, a probable helicase involved in DNA repair and possibly replication, and peptide synthase 1; Saccharomyces cerevisiae Pab1p-dependent poly(A) nuclease PAN2 subunit, required for shortening mRNA poly(A) tails; Caenorhabditis elegans and Mus musculus CAF1, transcription factor CCR4-associated factor 1; Xenopus laevis XPMC2, prevention of mitotic catastrophe in fission yeast; Drosophila melanogaster egalitarian, oocyte specification and axis determination, and exuperantia, establishment of oocyte polarity; H.sapiens HEM45, expressed in tumour cell lines and uterus and regulated by oestrogen; and 31 open reading frames including one in Methanococcus jannaschii . Examination of a multiple sequence alignment and two three-dimensional structures of proofreading domains has allowed definition of the core sequence, structural and functional elements of this exonuclease domain.
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PMID:The proofreading domain of Escherichia coli DNA polymerase I and other DNA and/or RNA exonuclease domains. 939 23

The human ISG20/HEM45 gene was identified independently on the basis of its increased level of expression in response to either interferon or estrogen hormone. Notably, the encoded protein is homologous with members of the 3' to 5' exonuclease superfamily that includes RNases T and D, and the proofreading domain of Escherichia coli DNA polymerase I. We provide here direct biochemical evidence that Isg20 acts as a 3' to 5' exonuclease in vitro. This protein displays a pH optimum of approximately 7.0, prefers Mn2+ as a metal cofactor, and degrades RNA at a rate that is approximately 35-fold higher than its rate for single-stranded DNA. Along with RNase L, Isg20 is the second known RNase regulated by interferon. Previous data showed that Isg20 is located in promyelocytic leukemia (PML) nuclear bodies, known sites of hormone-dependent RNA polymerase II transcription and oncogenic DNA viral transcription and replication. The combined data suggest a potential role for Isg20 in degrading viral RNAs as part of the interferon-regulated antiviral response and/or cellular mRNAs as a regulatory component of interferon and estrogen signaling.
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PMID:The human interferon- and estrogen-regulated ISG20/HEM45 gene product degrades single-stranded RNA and DNA in vitro. 1140 64