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)

To test whether any specific 5' precursor sequences are required for the processing of pre-16S rRNA, constructs were studied in which large parts of the 5' leader sequence were replaced by the coliphage lambda pL promoter and adjacent sequences. Unexpectedly, few full-length transcripts of the rRNA were detected after the pL promoter was induced, implying that either transcription was poor or most of the rRNA chains with lambda leader sequences were unstable. Nevertheless, sufficient transcription occurred to permit the detection of processing by S1 nuclease analysis. RNA transcripts in which 2/3 of the normal rRNA leader was deleted (from the promoter up to the normal RNase III cleavage site) were processed to form the normal 5' terminus. Thus, most of the double-stranded stem that forms from sequences bracketing wild-type 16S pre-rRNA is apparently not required for proper processing; the expression of such modified transcripts, however, must be increased before the efficiency of processing of the 16S rRNA formed can be assessed.
J Bacteriol 1987 Dec
PMID:Processing of Escherichia coli 16S rRNA with bacteriophage lambda leader sequences. 244 28

We isolated and characterized the rRNA operons of murine Chlamydia trachomatis. By exhaustively screening a library of chlamydial DNA and by blot hybridization of genomic DNA, we showed that there are only two rRNA operons in C. trachomatis. S1 nuclease protection and primer extension analysis were used to map the 5' and 3' ends of the mature 16S and 23S transcripts in both rRNA cistrons and, additionally, to demonstrate the lack of intervening sequences in these genes. The 5' ends of the presumed primary rRNA transcript were located and found to originate at two tandem sites separated by 100 base pairs. The two tandem chlamydial rDNA transcripts were not differentially regulated. Their products were coordinately expressed and were detectable as early as 9 h postinfection. However, the upstream transcript was only 10% as abundant as the downstream transcript. The sequences surrounding the transcription initiation sites bore little homology with each other or with the classic Escherichia coli -10 and -35 promoter sequences. This finding suggests that chlamydial transcription signals may differ from those of previously studied procaryotes.
J Bacteriol 1987 Dec
PMID:Chlamydial rRNA operons: gene organization and identification of putative tandem promoters. 244 32

The branched RNA (msdRNA) of M. xanthus consists of 77 bases. The 20th rG residue is linked to the 5' end of msDNA, consisting of 162 bases, by a 2', 5' phosphodiester linkage. The msdRNA coding region is located on the chromosome in the opposite orientation to the msDNA coding region, with the 3' ends overlapping by eight bases. S1 nuclease mapping experiments indicate that the primary product of msdRNA is much longer at both the 5' and 3' ends (approximately 375 bases). Because of homologous sequences upstream of the msdRNA and msDNA coding regions, the precursor RNA molecule is considered to form an extremely stable stem-and-loop structure (delta G = -210 kcal). We propose a novel mechanism of DNA synthesis in which the stem-and-loop structure serves as a primer as well as a template to form the branched RNA-linked msDNA.
Cell 1987 Dec 24
PMID:Structure of msDNA from Myxococcus xanthus: evidence for a long, self-annealing RNA precursor for the covalently linked, branched RNA. 244 73

We have determined the molecular defect of the Drosophila melanogaster myosin heavy chain (MHC) mutation Mhc and the mutation's effect on indirect flight muscle, jump muscle, and larval intersegmental muscle. We show that the Mhc1 mutation is essentially a null allele which results in the dominant-flightless and recessive-lethal phenotypes associated with this mutant (Mogami, K., P. T. O'Donnell, S. I. Bernstein, T. R. F. Wright, C. P. Emerson, Jr. 1986. Proc. Natl. Acad. Sci. USA. 83:1393-1397). The mutation is a 101-bp deletion in the MHC gene which removes most of exon 5 and the intron that precedes it. S1 nuclease mapping indicates that mutant transcripts follow two alternative processing pathways. Both pathways result in the production of mature transcripts with altered reading frames, apparently yielding unstable, truncated MHC proteins. Interestingly, the preferred splicing pathway uses the more distal of two available splice donor sites. We present the first ultrastrutural characterization of a completely MHC-null muscle and show that it lacks any discernable thick filaments. Sarcomeres in these muscles are completely disorganized suggesting that thick filaments play a critical role in sarcomere assembly. To understand why the Mhc1 mutation severely disrupts indirect flight muscle and jump muscle function in heterozygotes, but does not seriously affect the function of other muscle types, we examined the muscle ultrastructure of Mhc1/+ heterozygotes. We find that these organisms have a nearly 50% reduction in the number of thick filaments in indirect flight muscle, jump muscle, and larval intersegmental muscle. In addition, aberrantly shaped thick filaments are common in the jump muscle and larval intersegmental muscle. We suggest that the differential sensitivity of muscle function to the Mhc1 mutation is a consequence of the unique myofilament arrays in each of these muscles. The highly variable myofilament array of larval intersegmental muscle makes its function relatively insensitive to changes in thick filament number and morphology. Conversely, the rigid double hexagonal lattice of the indirect flight muscle, and the organized lattice of the jump muscle cannot be perturbed without interfering with the specialized and evolutionarily more complex functions they perform.
J Cell Biol 1988 Dec
PMID:Molecular and ultrastructural defects in a Drosophila myosin heavy chain mutant: differential effects on muscle function produced by similar thick filament abnormalities. 246 66

Nuclease-resistant alpha-anomeric DNA:beta-RNA hybrids are inhibitors of Escherichia coli RNase H, and Drosophila embryo RNase H. RNase H activities were measured by polyacrylamide gel electrophoresis, employing a short substrate, (A)12:d[G-G-(T)12-G-G], or by acid-solubility techniques, using a long substrate, poly(A):poly(dT). Strand exchanges which could be responsible for the observed inhibition have been ruled out by S1 nuclease experiments and by using inhibitors which do not allow strand exchange. Our results suggest that RNase H, for which DNA:RNA duplexes are the natural substrates, binds to non-physiological alpha-DNA:RNA hybrids and is consequently inhibited. These hybrids also inhibit the RNA-dependent DNA polymerase activity of M-MLV reverse transcriptase, therefore appearing as potential inhibitors of at least two reverse transcriptase activities. However, the inhibitory effect of these hybrids with respect to M-MLV reverse transcriptase is also observed with the single-stranded alpha-DNA itself. Unexpectedly, polymerase activity is highly stimulated by alpha-oligos, analogous in their sequence to the beta primer used at a concentration unable to generate a detectable synthesis. These results suggest that the inhibition of reverse transcriptase activity with the alpha:beta may occur at different levels.
Gene 1988 Dec 10
PMID:Alpha-anomeric DNA: beta-RNA hybrids as new synthetic inhibitors of Escherichia coli RNase H, Drosophila embryo RNase H and M-MLV reverse transcriptase. 246 72

A Xenopus laevis mRNA encoding a cytokeratin of the basic (type II) subfamily that is expressed in postgastrulation embryos was cDNA-cloned and sequenced. Comparison of the deduced amino acid sequence of this polypeptide (513 residues, calculated mol. wt 55,454; Mr approximately 58,000 on SDS-PAGE) with those of other cytokeratins revealed its relationship to certain type II cytokeratins of the same and other species, but also remarkable differences. Using a subclone representing the 3'-untranslated portion of the 2.4 kb mRNA encoding this cytokeratin, designated XenCK55(5/6), in Northern blot experiments, we found that it differs from the only other Xenopus type II cytokeratin known, i.e. the simple epithelium-type component XenCK1(8), in that it is absent in unfertilized eggs and pregastrulation embryos. XenCK55(5/6) mRNA was first detected at gastrulation (stage 11) and found to rapidly increase during neurulation and further development. It was also identified in Xenopus laevis cultured kidney epithelial cells of the line A6 and in the adult animal where it is a major polypeptide in the oesophageal mucosa but absent in most other tissues examined. The pattern of XenCK55(5/6) expression during embryonic development was similar to that reported for the type I polypeptides of the 'XK81 subfamily' previously reported to be embryo-specific and absent in adult tissues. Therefore, we used a XK81 mRNA probe representing the 3'-untranslated region in Northern blots, S1 nuclease and hybrid-selection-translation assays and found the approximately 1.6 kb XK81 mRNA and the resulting protein of Mr approximately 48,000 not only in postgastrula embryos and tadpoles but also in the oesophagus of adult animals. Our results show that both these type II and type I cytokeratins are synthesized only on gastrulation and are very actively produced in early developmental stages but is continued in at least one epithelium of the adult organism. These observations raise doubts on the occurrence of Xenopus cytokeratins that are strictly specific for certain embryonic or larval stages and absent in the adult. They rather suggest that embryonically expressed cytokeratins are also produced in some adult tissues, although in a restricted pattern of tissue and cell type distribution.
Development 1988 Dec
PMID:Expression of intermediate filament proteins during development of Xenopus laevis. III. Identification of mRNAs encoding cytokeratins typical of complex epithelia. 247 54

We have cloned the human perforin (P1) gene and sequenced 6.2-kb genomic DNA, containing 1.4-kb 5'-flanking region, the 5' untranslated region, the complete coding region and the beginning of the 3' untranslated region. The P1 gene including at least 95-bp 3' untranslated region is organized in only three exons: the first exon (97 bp) contains all but four nucleotides of the 5' untranslated region and was determined by primer extension and S1 nuclease mapping. This exon is separated by 1.7 kb from the second exon containing the remaining (4 bp) 5' untranslated region, the leader peptide and the N-terminal region of P1 up to--but not including--the C9 homologous region. The third exon is separated by a 1.2-kb intron and contains the remainder of the molecule, including at least 90 bp of the 3' untranslated region. This simple gene organization differs from that of the more complicated C9 gene. Because of the unusual intron in the 5' untranslated sequence the transcription initiation (cap) site is located almost 1.8 kb upstream of the ATG start signal. The more immediate 5' flanking sequence contains a CCAAT and GC box but lacks other known promoter elements. Instead, we find three different sequence repeats. One of them, a hexanucleotide sequence with the consensus GCCCTG of unknown significance occurs 19 times within a stretch of 240 bp. Further upstream we localized sequences homologous to the following enhancer and promoter elements: c-fos proto-oncogene, IFN-gamma and phorbol ester response elements, five cAMP response elements, and three motifs corresponding to general inducer elements. In addition, a sequence conserved in the 5'-flanking region of several T cell genes was identified. The 5' flanking regions of P1. CCP1 (granzyme B) and CCP2 (granzyme C) (kindly provided by Dr. Bleackley) contain as only significant homology cAMP response elements. These findings are consistent with a tight control and regulation of P1, which appears to be distinct from that of granzymes.
J Immunol 1989 Dec 15
PMID:Structure of the human perforin gene. A simple gene organization with interesting potential regulatory sequences. 248 Mar 91

A genomic clone for the Sarcophaga lectin gene was isolated. This gene was a compact single copy gene. Two transcription initiation sites were located by S1 nuclease mapping and primer extension. However, transcription from one of these initiation sites was much greater than that from the other site under all conditions in which this gene was expressed. This gene was found to be transcribed efficiently in a nuclear extract of NIH-Sape-4 cells, an embryonic cell line of Sarcophaga synthesizing Sarcophaga lectin constitutively, but not in that of Ehrlich ascites tumor cells. These results suggested that the former extract contains a specific transcription factor(s) for this gene that is not present in the nuclear extract of Ehrlich cells.
Biochim Biophys Acta 1989 Dec 22
PMID:Cloning and in vitro transcription of the Sarcophaga lectin gene. 248 Aug 9

A transcript, of about 650 nucleotides (nt), from the Streptomyces subtilisin-inhibitor-encoding gene (ssi) was identified by Northern hybridization analysis in both the original strain, S. albogriseolus S-3253, and the transformant, S. lividans 66, carrying an expression plasmid with the cloned ssi gene, pJS1. These results were quite consistent with the analysis of the major transcriptional start point (tsp; at nt 429) by primer extension experiments and the transcriptional end point (at nt 1065) by S1 nuclease mapping of the ssi gene. Deletion experiments on the 5'-flanking region of the major tsp suggested that two promoter sequences control the expression of ssi. The more proximal of these putative promoters appears to be homologous to the -45 to -25 region of the ctc promoter in Bacillus subtilis and includes a direct repeat in the -10 region.
Gene 1989 Dec 14
PMID:Analysis of transcriptional control regions in the Streptomyces subtilisin-inhibitor-encoding gene. 248 28

The quadriflagellate, unicellular, colorless alga, Polytomella agilis, contains several distinct microtubule arrays. To study the genetic basis of microtubule heterogeneity in P. agilis, we characterized its tubulin(Tub)-encoding genes (tub). The three beta tub genes detected in blots of P. agilis DNA were isolated from a genomic library. The structure and organization of the genes were examined by restriction mapping and nucleotide (nt) sequencing. S1 nuclease protection studies showed that all three genes are expressed. The predicted amino acid (aa) sequences are more than 98% conserved with the Chlamydomonas reinhardtii and Volvox carteri beta-Tubs, underscoring the close phylogenetic relationship of these species. Evolutionary divergence among the P. agilis genes is demonstrated by differences in intron number, nt sequences in noncoding regions, and silent nt substitutions in the coding regions. However, the proteins encoded by the beta 1 and beta 3 tub genes are identical; the beta 2 gene product differs by one conservative aa substitution. These results are in striking contrast to the C-terminal aa diversity reported within beta tub gene families in animal, higher plant and fungal systems. The data support the hypothesis that those tub genes whose products assemble into axonemal microtubules are subject
Gene 1989 Dec 14
PMID:Structure of the three beta-tubulin-encoding genes of the unicellular alga, Polytomella agilis. 253 30


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