Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.1.27.3 (RNase T1)
 1,228 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Using purified RNA from HeLa cells, we have synthesized and cloned a cDNA encoding an almost entire 7 S K RNA. This cDNA probe was used to isolate 7 S K RNA gene sequences from a human genomic library by high-stringency colony hybridization. In order to differentiate between functional genes and related sequences, we have used a rapid in-vitro transcription assay of purified phage DNA. With this additional screening criterion applied to selected clones, we have obtained one recombinant phage that contained a complete 7 S K RNA gene and, immediately adjacent to its 3' end, a truncated pseudogene. The nucleotide sequence of both genes including the flanking regions has been determined. The functional integrity of the isolated 7 S K RNA gene was verified by in-vitro transcription studies with cell-free extracts and by fingerprinting of the specific transcripts with ribonuclease T1. Under optimal ionic conditions, the transcription efficiency in vitro of this 7 S K RNA gene was found to be comparable to that of a human 7 S K RNA in vitro depends on 5'-flanking sequences. The region up to position -67 was determined to be essential for efficient transcription in vitro of 7 S K RNA. While apparently a variety of 7 S K related sequences is distributed within the human genome, hybridization of 5'-flanking sequences to genomic DNA revealed that possibly not more than one copy of this gene is present per haploid genome.
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PMID:Structural and functional analysis of a human 7 S K RNA gene. 244 10

A bacteriophage lambda clone containing a 15.4-kb human DNA fragment was isolated and found to contain a glycine tRNA gene and, 758 bp away, a pseudogene, both with an anticodon of GCC. The nucleotide (nt) sequence of a 1362-bp segment of this clone, encompassing the gene, pseudogene, and their flanking regions, was determined. The gene and pseudogene have an identical sequence of eight nt (5'-CAGCTGGA-3') in their 5'-flanking regions immediately preceding the coding regions, as well as characteristic transcription termination sites of five consecutive T nt in the 3'-flanking regions. Neither of these genes has intervening sequences. Only one of the two genes was efficiently transcribed in vitro by RNA polymerase III in a HeLa cell-free system. During the course of transcription, primary transcripts of one gene were processed to yield mature-sized products. In contrast, the level of transcription of the second gene was significantly less than that of the first, and no mature-sized products could be detected. The nt sequence of the inefficiently transcribed gene has two base substitutions compared to the sequence of the efficiently transcribed gene, and the DNA sequence predicted from the human placental tRNAGlyGCC sequence. One of these nt substitutions is a C to T transition in the TTCG sequence within the B block of the characteristic internal split promoter sequence. The precursor-product relationships of the tRNA transcripts were established by comparing the RNase T1 and RNase A fingerprints of the precursors and products.
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PMID:Nucleotide sequence and transcription of a human glycine tRNAGCC gene and nearby pseudogene. 301 33

We have cloned and partially characterized 24 loci from the human genome which are complementary to U1, U2, or U3, the three major species of small nuclear RNA (snRNA) in HeLa cells. When compared to the known U1 (human) and U2 (rat) snRNA sequences, the DNA sequences we report here for the complementary regions from two of the clones, U1.11 and U2.7, reveal the presence of truncated and divergent gene copies. Furthermore, most if not all of the 24 cloned loci contain gene copies that are significantly divergent from the homologous HeLa snRNA species because DNA from every recombinant phage except U1.7 and U1.15 proved unable to form snRNA.DNA hybrids which protect full-length HeLa snRNA from ild digestion with ribonuclease T1. Hence, we refer to these loci as snRNA pseudogenes. In both clones U1.11 and U2.7, an element of the dominant middle repetitive DNA sequence family in the human genome, the Alu family, is located upstream from the snRNA pseudogene and in the same orientation. Alu elements in the same location and orientation relative to bona fide genes have previously been found in the human beta-globin gene cluster [Duncan, C. H., Biro, P. A., Choudary, P. V., Elder, J. T., Wang, R. C., Forget, G. B., deRiel, J. K. & Weissman, S. M. (1979) Proc. Natl. Acad. Sci. USA 76, 5095-5099]. We discuss the significance of these findings in relation to the nature of snRNA multigene families and other reported examples of pseudogenes.
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PMID:Abundant pseudogenes for small nuclear RNAs are dispersed in the human genome. 616 10