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)

The adenovirus type 2 fiber mutant H2 ts 125 synthesized an unstable, temperature-sensitive fiber polypeptide with an apparent mol. wt. smaller by 2500 than the wild-type (62 K). The polypeptide of 59.5 K was found to be stable at the permissive temperature (33 degrees C). H2 ts 125 fiber synthesized in reticulocyte lysates had the same apparent mol. wt. of 59.5 K as the mutant fiber produced in vivo. Neither structural nor functional differences between wild-type and mutant fibers were detected in the N-terminal and C-terminal sequences, excluding the occurrence of a new initiation or termination codon. Restriction analysis of H2 ts 125 DNA also ruled out the hypothesis of a deletion mutant. The 59.5 K mutant fiber unit was normally glycosyated, N-acetylated, assembled into 6S oligomeric fiber and incorporated into virions. DNA sequencing of the H2 ts 125 fiber gene revealed two point mutations at nucleotides 3970 (C*TT leads to T*TT) and 4958 (GC*T leads to GT*T), corresponding to two amino acid changes at positions 105 and 434, respectively. The 105 mutation consisted of a conservative change Leu leads to Phe; the 434 interchange was Ala leads to Val, usually considered as nonconservative. The possibility of a donor site for splicing created by the mutation at codon GTT was eliminated on the basis of S1 nuclease analysis data. All these results suggested that either one or both mutations concerned highly organized domain(s) of the fiber polypeptide chain, resulting in aberrant mobility in SDS-polyacrylamide gels and temperature-sensitivity.
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PMID:Biochemical and genetical characterization of a fiber-defective temperature-sensitive mutant of type 2 adenovirus. 657 1

By using a combination of Northern blot hybridization with strand-specific DNA probes, S1 nuclease protection, and sequencing of oligo-dT-primed cDNA clones, we have identified a 0.8 kb poly(A)-containing RNA encoded by the H-strand of the mouse mitochondrial D-loop region. The 5' end of the RNA maps to nucleotide 15417, a region complementary to the start of tRNA(Pro) gene and the 3' polyadenylated end maps to nucleotide 16295 of the genome, immediately upstream of tRNA(Phe) gene. The H-strand D-loop region encoded transcripts of similar size are also detected in other vertebrate systems. In the mouse, rat, and human systems, the 3' ends of the D-loop encoded RNA are preceded by conserved sequences AAUAAA, AAUUAA, or AACUAA, that resemble the polyadenylation signal. The steady-state level of the RNA is generally low in dividing or in vitro cultured cells, and markedly higher in differentiated tissues like liver, kidney, heart, and brain. Furthermore, an over 10-fold increase in the level of this RNA is observed during the induced differentiation of C2C12 mouse myoblast cells into myotubes. These results suggest that the D-loop H-strand encoded RNA may have yet unknown biological functions. A 20 base pair DNA sequence from the 3' terminal region containing the conserved sequence motif binds to a protein from the mitochondrial extracts in a sequence-specific manner. The binding specificity of this protein is distinctly different from the previously characterized H-strand DNA termination sequence in the D-loop or the H-strand transcription terminator immediately downstream of the 16S rRNA gene. Thus, we have characterized a novel poly(A)-containing RNA encoded by the H-strand of the mitochondrial D-loop region and also identified the putative ultimate termination site for the H-strand transcription.
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PMID:Identification of a stable RNA encoded by the H-strand of the mouse mitochondrial D-loop region and a conserved sequence motif immediately upstream of its polyadenylation site. 753 62

Structural differences between native yeast tRNA(Phe), its in vitro transcript and the U8G mutant have been investigated using metal ion-induced hydrolysis and nuclease digestion. Differences in the solution structure of the molecules involve four regions: the D- and T-loops, the variable region and the anticodon loop. Efficiency of the Pb(II); Eu(II)-, Mn(II)- and Mg(II)-induced hydrolysis at the main cleavage sites in the D-loop is significantly reduced for unmodified tRNAs. Moreover, only the in vitro transcripts are susceptible for cleavage in the T-loop and entire anticodon loop. Other changes in the transcript molecule involve 50-fold enhancement of S1 nuclease digestion at p36, weak cleavages in the D-loop and lack of some digestion sites in the T-loop. The nuclease V1 digestion patterns are very similar for studied molecules. Changes in the pattern of hydrolysis of the D-loop caused by mutation of the conservative base U8 to G are detected by metal-induced hydrolysis only. Our results indicate clearly that metal ions and enzymatic probes monitor different features of RNA structure and their combined use is highly advantageous in studying subtle structural changes in tRNA.
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PMID:Effect of modified nucleotides on structure of yeast tRNA(Phe). Comparative studies by metal ion-induced hydrolysis and nuclease mapping. 881 22

Phenylalanine ammonia-lyase (PAL; EC 4.3.1.5) genomic sequences were isolated from bean (Phaseolus vulgaris L.) genomic libraries using elicitor-induced bean PAL cDNA sequences as a probe. Southern blot hybridization of genomic DNA fragments revealed three divergent classes of PAL genes in the bean genome. Polymorphic forms were observed within each class. The nucleotide sequences of two PAL genes, gPAL2 (class II) and gPAL3 (class III), were determined. gPAL2 contains an open reading frame encoding a polypeptide of 712 amino acids, interrupted by a 1720 bp intron in the codon for amino acid 130. gPAL3 encodes a polypeptide of 710 amino acids showing 72% similarity with that encoded by gPAL2, and contains a 447 bp intron at the same location. At the nucleotide level, gPAL2 and gPAL3 show 59% sequence similarity in exon I, 74% similarity in exon II, and extensive sequence divergence in the intron, 5' and 3' flanking regions. S1 nuclease protection identified transcription start sites of gPAL2 and gPAL3 respectively 99 bp and 35 bp upstream from the initiation codon ATG, and showed that gPAL2 but not gPAL3 was activated by elicitor, whereas both were activated by wounding of hypocotyls. The 5' flanking region of both genes contain TATA and CAAT boxes, and sequences resembling the SV40 enhancer core. gPAL2 contains a 40 bp palindromic sequence and a 22 bp motif that are also found at similar positions relative to the TATA box in 5' flanking regions of other elicitor-induced bean genes.
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PMID:Phenylalanine ammonia-lyase gene organization and structure. 2427 98


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