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 cp35 gene, encoding an annexin I (AnxI) cropsac 35-kDa protein (cp35) from the pigeon, consists of 13 exons and twelve introns. The borders of exons 2-13 were mapped by comparison with the known cDNA sequence. A 5-kb sequence containing exons 1, 2, and 3, and 1.4 kb of 5'-flanking DNA, is presented. The transcription start point was mapped by S1 nuclease protection. The region of the cp35 mRNA sequence, which we had previously shown to be profoundly different from mammalian anxI, is located in the first half of exon 3. Whereas human anxI is known to be single copy, Southern analysis of pigeon genomic DNA and genomic clones demonstrated multiple anxI genes in the pigeon, diverging significantly in their 5'-termini. Pigeon vimentin, on the other hand, is encoded by a single-copy gene as it is in other birds and mammals. These experiments have demonstrated that the cp35 mRNA is transcribed from its individual gene and is not a product of alternative processing of the pigeon homolog of mammalian anxI. We speculate that the diversification of anxI genes in Columbid birds allowed the recruitment of one of these genes (cp35) for unique regulation by prolactin in the absence of post-translational regulation via residues encoded by exons 2 and 3.
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PMID:Structure of the gene encoding columbid annexin Icp35. 183 9

Regulation of slow troponin C gene expression was examined in both skeletal and cardiac muscle at various stages of development in chicken. The steady-state levels of troponin C mRNA were initially measured by Northern blot analysis. It was observed that the level of troponin C mRNA reached its maximum in both skeletal and cardiac muscle of 16- to 18-day-old embryos. A drop in troponin C mRNA level was observed just prior to hatching. The level of actin mRNA, myosin heavy chain mRNA, and mRNA for a nonmuscle protein, vimentin, was also similarly regulated during development of chicken muscles. Further studies were carried out to determine the level of slow troponin C mRNA using nuclease S1 protection analysis. A significant amount of slow troponin C mRNA was found in the skeletal muscle of adult chicken, which predominantly consists of the fast isoform of troponin C. This observation suggests the possibility of post-transcriptional control of slow troponin C synthesis in skeletal muscle. Primary cultures of cardiac myocytes were also used to determine how the troponin C mRNA level is regulated in a culture of cardiac muscle cells. Measurements of the steady-state levels of slow troponin C mRNA by nuclease S1 protection analysis show that it was maximal in 60-h-old cultures. A drop in the level of this mRNA was observed after these cells were maintained in culture for 4 days.
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PMID:Developmentally regulated slow troponin C messenger RNA in chicken skeletal and cardiac muscles. 284 45

Vimentin is a growth-regulated gene whose mRNA levels increase severalfold after stimulation of quiescent cells. We have isolated and sequenced a genomic fragment of human DNA containing the vimentin 5'-flanking sequence and untranslated region. S1 nuclease analysis was used to determine the transcription initiation site. Deletion mutants of the promoter region were constructed, linked to a chloramphenicol acetyltransferase gene, and analyzed for transient expression by transfection into BALB/c 3T3 cells. These experiments revealed the presence in the human vimentin promoter region of a negative-regulatory element, flanked by positive elements. The most 5' of the positive elements is able to overcome the effects of the negative element. Analysis of these deletion constructs in stable cell lines confirmed the results of the transient assays. Using these stable cell lines, we can also demonstrate that the vimentin promoter region can confer platelet-derived growth factor inducibility to a linked chloramphenicol acetyltransferase gene and that the sequences required for this inducibility reside between positions -241 and +73.
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PMID:Functional analysis and growth factor regulation of the human vimentin promoter. 343 46

Four different genomic clones which contain the genes coding for epidermal keratins Ia (mol. wt. approximately 68 000), Ib (68 000), III (60 000) and VIb (54 500) have been selected using cDNA probes and identified by hybrid-selection translation. The genes vary considerably in length, primarily due to differences in intron sizes: keratin Ia, 9.3 kb (approximately 2.55 kb total exons); keratin Ib, 6.0 kb (2.25 kb exons); keratin III, 6.0 kb (2.2 kb exons); keratin VIb, 4.4 kb (1.85 kb exons). The genes for all three representatives of the basic (type II) cytokeratin subfamily, i.e., keratins Ia, Ib and III, contain eight introns of variable sizes (0.1-1.8 kb) and their exon patterns are very similar. The gene coding for keratin VIb, a representative of the acidic (type I) subfamily, contains seven introns, and the size pattern of its five innermost exons closely resembles that of the genes of the type II keratins. Most of the introns are located in regions coding for the alpha-helical cores of these proteins. Mapping of the intron positions by the S1 nuclease technique and sequencing of some exon-intron boundaries has revealed that some of the introns of all four keratin genes have similar positions to each other and to those of the hamster vimentin gene.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Characterization of bovine keratin genes: similarities of exon patterns in genes coding for different keratins. 608 95

As previously shown, type III intermediate filaments (IFs) select from a mixture of linear mouse genomic DNA fragments mobile and repetitive, recombinogenic sequences that have also been identified in SDS-stable crosslinkage products of vimentin and DNA isolated from intact fibroblasts. Because these sequences also included homopurine.homopyrimidine (Pu.Py) tracts known to adopt triple-helical conformation under superhelical tension, and because IF proteins are single-stranded (ss) and supercoiled DNA-binding proteins, it was of interest whether they have a particular affinity for triplex DNA. To substantiate this, IF-selected DNA fragments harboring a (Pu.Py) segment and synthetic d(GA)(n) microsatellites were inserted into a vector plasmid and the constructs analyzed for their capacity to interact with IF proteins. Band shift assays revealed a substantially higher affinity of the IF proteins for the insert-containing plasmids than for the empty vector, with an activity decreasing in the order of vimentin > glial fibrillary acidic protein > desmin. In addition, footprint analyses performed with S1 nuclease, KMnO(4), and OsO(4)/bipyridine showed that the (Pu.Py) inserts had adopted triplex conformation under the superhelical strain of the plasmids, and that the IF proteins protected the triple-helical insert sequences from nucleolytic cleavage and chemical modification. All these activities were largely reduced in extent when analyzed on linearized plasmid DNAs. Because intramolecular triplexes (H-DNA) expose single-stranded loops, and the prokaryotic ssDNA-binding proteins g5p and g32p also protected at least the Pu-strand of the (Pu.Py) inserts from nucleolytic degradation, it seemed likely that the IF proteins take advantage of their ssDNA-binding activity in interacting with H-DNA. However, in contrast to g5p and E. coli SSB, they produced no clear band shifts with single-stranded d(GA)(20) and d(TC)(20), so that the interactions rather appear to occur via the duplex-triplex and triplex-loop junctions of H-DNA. On the other hand, the IF proteins, and also g32p, promoted the formation of intermolecular triplexes from the duplex d[A(GA)(20).(TC)(20)T] and d(GA)(20) and d(TC)(20) single strands, with preference of the Py (Pu.Py) triplex motif, substantiating an affinity of the proteins for the triplex structure as such. This triplex-stabilizing effect of IF proteins also applies to the H-DNA of (Pu.Py) insert-containing plasmids, as demonstrated by the preservation of intramolecular triplex-vimentin complexes upon linearization of their constituent supercoiled DNAs, in contrast to poor complex formation from free, linearized plasmid DNA and vimentin. Considering that (Pu.Py) sequences are found near MAR/replication origins, in upstream enhancer and promoter regions of genes, and in recombination hot spots, these results might point to roles of IF proteins in DNA replication, transcription, recombination, and repair.
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PMID:Interaction in vitro of type III intermediate filament proteins with triplex DNA. 1201 95

The selection of DNA fragments containing simple d(GT)(n) and composite d(GT)(m). d(GA)(n) microsatellites during affinity binding of mouse genomic DNA to type III cytoplasmic intermediate filaments (cIFs) in vitro, and the detection of such repeats, often as parts of nuclear matrix attachment region (MAR)-like DNA, in SDS-stable DNA-vimentin crosslinkage products isolated from intact fibroblasts, prompted a detailed study of the interaction of type III cIF proteins with left-handed Z-DNA formed from d(GT)(17) and d(CG)(17) repeats under the topological tension of negatively supercoiled plasmids. Although d(GT)(n) tracts possess a distinctly lower Z-DNA-forming potential than d(CG)(n) tracts, the filament proteins produced a stronger electrophoretic mobility shift with a plasmid carrying a d(GT)(17) insert than with plasmids containing different d(CG)(n) inserts, consistent with the facts that the B-Z transition of d(GT)(n) repeats requires a higher negative superhelical density than that of d(CG)(n) repeats and the affinity of cIF proteins for plasmid DNA increases with its superhelical tension. That both types of dinucleotide repeat had indeed undergone B-Z transition was confirmed by S1 nuclease and chemical footprinting analysis of the plasmids, which also demonstrated efficient protection by cIF proteins from nucleolytic and chemical attack of the Z-DNA helices as such, as well as of the flanking B-Z junctions. The analysis also revealed sensibilization of nucleotides in the center of one of the two strands of a perfect d(CG)(17) insert toward S1 nuclease, indicating cIF protein-induced bending of the repeat. In all these assays, vimentin and glial fibrillary acidic protein (GFAP) showed comparable activities, versus desmin, which was almost inactive. In addition, vimentin and GFAP exhibited much higher affinities for the Z-DNA conformation of brominated, linear d(CG)(25) repeats than for the B-DNA configuration of the unmodified oligonucleotides. While double-stranded DNA was incapable of chasing the Z-DNA from its protein complexes, and Holliday junction and single-stranded (ss)DNA were distinguished by reasonable competitiveness, phosphatidylinositol (PI) and, particularly, phosphatidylinositol 4,5-diphosphate (PIP(2)) turned out to be extremely potent competitors. Because PIP(2) is an important member of the nuclear PI signal transduction cascade, it might exert a regulatory influence on the binding of cIF proteins to Z- and other DNA conformations. From this interaction of cIF proteins with Z- and bent DNA and their previously detected affinities for MAR-like, ss, triple helical, and four-way junction DNA, it may be concluded that the filament proteins play a general role in such nuclear matrix-associated processes as DNA replication, recombination, repair, and transcription.
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PMID:Interaction in vitro of type III intermediate filament proteins with Z-DNA and B-Z-DNA junctions. 1280 14