Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: 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)

Mapping of the 5' and 3' ends of the Drosophila myosin alkali light chain (MLC-ALK) mRNA by S1 nuclease and primer extension assays has shown that the primary transcripts are identical irrespective of the time in development that the RNA was prepared. As shown by S1 nuclease experiments these transcripts are alternatively spliced in a tissue-specific fashion generating mRNAs that encode tissue-specific protein isoforms. Antibodies were raised to synthetic peptides identical in sequence to the unique portion of each protein. Western blots of one-dimensional polyacrylamide gels using the type-specific antibodies confirmed and extended the results obtained from the S1 nuclease experiments. The indirect flight muscle is the only tissue in the adult that accumulates the alternatively spliced mRNA. The choice between splicing pathways involves the use of a nonconsensus 3' splice junction in larvae and in the tubular muscles of adults, whereas in the indirect flight muscle of the adult only consensus sequences are utilized. The involvement of a trans-acting factor to activate the nonconsensus splice site in the myotubes of larvae and the tubular myotubes of adults is proposed.
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PMID:The indirect flight muscle of Drosophila accumulates a unique myosin alkali light chain isoform. 310 19

We have isolated and characterized two kinds of cDNA for the chicken cardiac myosin alkali light chain. The sequences of the two cDNAs are identical, except for a notable divergence in part of the 3' untranslated sequence. By analysis of isolated genomic clones, it was shown that the genomic sequences corresponding to the different sequences in the 3' untranslated regions of the two mRNAs were arranged within a limited part of a single stretch of DNA; also the two distinct 3' untranslated regions of the two mRNAs shared part of the last exon, which was 0.6 x 10(3) base-pairs long. There are two canonical acceptor sites available for RNA splicing in the last exon, the first being located at the 5' end of the exon, and the second at 370 base-pairs downstream from this end. Together with analysis by S1 nuclease mapping, the foregoing results lead us to conclude that, by the differential use of these two acceptor sites, a single gene generates two distinct mRNAs of 1.45 x 10(3) base-pairs and 1.1 x 10(3) base-pairs with or without the 5' half of the last exon. The two mRNAs appear to utilize the same modified poly(A) signal, AGTAAA, rather than the authentic AATAAA sequence present about 30 base-pairs downstream from the poly(A) attachment sites. This is probably because another consensus G + T-rich sequence is present at an appropriate distance from the AGTAAA sequence, but not from the AATAAA sequence. The gene for the cardiac myosin alkali light chain has proved to be expressed in ventricular muscle and in atrial and anterior latissimus dorsi muscles, the last of these being characteristic of slow skeletal muscle. In these muscles, two kinds of mRNA for the cardiac myosin alkali light chain, identical with those in ventricular muscle, were expressed and their relative amount in each tissue was almost the same as that in ventricular muscle.
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PMID:Single chicken cardiac myosin alkali light-chain gene generates two different mRNAs by alternative splicing of a complex exon. 321 Feb 43

A cDNA clone, SMHC-29, encoding the light meromyosin of smooth muscle myosin heavy chain (MHC), was isolated from a rabbit uterus cDNA library constructed in phage lambda gt11. This smooth muscle MHC cDNA demonstrates significant nucleotide and amino acid sequence homologies with known sarcomeric MHC genes from rabbit, rat skeletal, and nematode body wall myosin, and even with nonmuscle MHC gene from a slime mold (Dictyostelium discoideum), suggesting that smooth muscle, striated muscle, and nonmuscle MHC genes diverged from a common ancestor. The deduced amino acid sequences of the smooth muscle light meromyosin show very similar periodic distributions of hydrophobic and charged residues as found for the light meromyosin of striated muscle MHCs together with a high potential for alpha-helical formation, indicating an alpha-helical coiled-coil structure for the smooth muscle light meromyosin sequences. Furthermore, S1 nuclease mapping has revealed that this smooth muscle MHC gene for SMHC-29 is specifically expressed in smooth muscles of vascular and nonvascular types but not in the striated muscles or nonmuscle cells.
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PMID:Characterization of a mammalian smooth muscle myosin heavy chain cDNA clone and its expression in various smooth muscle types. 342 77

Through S1 nuclease mapping using a specific cDNA probe, we demonstrate that the slow myosin heavy-chain (MHC) gene, characteristic of adult soleus, is expressed in bulk hind limb muscle obtained from the 18-d rat fetus. We support these results by use of a monoclonal antibody (mAb) which is highly specific to the adult slow MHC. Immunoblots of MHC peptide maps show the same peptides, uniquely recognized by this antibody in adult soleus, are also identified in 18-d fetal limb muscle. Thus synthesis of slow myosin is an early event in skeletal myogenesis and is expressed concurrently with embryonic myosin. By immunofluorescence we demonstrate that in the 16-d fetus all primary myotubes in future fast and future slow muscles homogeneously express slow as well as embryonic myosin. Fiber heterogeneity arises owing to a developmentally regulated inhibition of slow MHC accumulation as muscles are progressively assembled from successive orders of cells. Assembly involves addition of new, superficial areas of the anterior tibial muscle (AT) and extensor digitorum longus muscle (EDL) in which primary cells initially stain weakly or are unstained with the slow mAb. In the developing AT and EDL, expression of slow myosin is unstable and is progressively restricted as these muscles specialize more and more towards the fast phenotype. Slow fibers persisting in deep portions of the adult EDL and AT are interpreted as vestiges of the original muscle primordium. A comparable inhibition of slow MHC accumulation occurs in the developing soleus but involves secondary, not primary, cells. Our results show that the fate of secondary cells is flexible and is spatially determined. By RIA we show that the relative proportions of slow MHC are fivefold greater in the soleus than in the EDL or AT at birth. After neonatal denervation, concentrations of slow MHC in the soleus rapidly decline, and we hypothesize that, in this muscle, the nerve protects and amplifies initial programs of slow MHC synthesis. Conversely, the content of slow MHC rises in the neonatally denervated EDL. This suggests that as the nerve amplifies fast MHC accumulation in the developing EDL, accumulation of slow MHC is inhibited in an antithetic fashion. Studies with phenylthiouracil-induced hypothyroidism indicate that inhibition of slow MHC accumulation in the EDL and AT is not initially under thyroid regulation. At later stages, the development of thyroid function plays a role in inhibiting slow MHC accumulation in the differentiating EDL and AT.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Slow myosin in developing rat skeletal muscle. 354 35

The 20-kD regulatory light chain (RLC) plays a central role in the regulation of smooth muscle contraction. Little is known about the structure or expression of smooth muscle myosin light chain (MLC) genes. A cDNA library was constructed in the expression vector, lambda gt-11, with mRNA derived from cultured rat aortic smooth muscle cells. Using antibody generated against tracheal smooth muscle myosin, three cDNA clones encoding a RLC were isolated, one of which, SmRLC-2, represents a full-length transcript of the RLC mRNA. The derived amino acid sequence shows 94.2% homology with the chicken gizzard RLC, and 70 and 52% homology with the rat skeletal and cardiac muscle MLC-2 proteins, respectively. Thus, the gene encoding the putative smooth muscle RLC appears to have originated by duplication of the same ancestor that gave rise to the sarcomeric MLC-2 genes. Contrary to the stringent tissue-specific expression of sarcomeric MLC-2 genes, RNA blot hybridization and S1 nuclease mapping demonstrates that the putative smooth muscle RLC gene is expressed in smooth, sarcomeric, and nonmuscle tissues at significant levels. Primer extension analysis suggests that the same promoter region is used in these different tissues. Thus the putative smooth muscle RLC gene appears to be a gene that is constitutively expressed in a large variety of cells and has a differentiated function in smooth muscle.
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PMID:Cloning and characterization of mammalian myosin regulatory light chain (RLC) cDNA: the RLC gene is expressed in smooth, sarcomeric, and nonmuscle tissues. 358 39

We have found evidence for two beta-like myosin heavy chains in humans, one cardiac and one skeletal. The cDNA sequences of the cardiac beta myosin heavy chain cDNA clone pHMC3 and the skeletal beta-like myosin heavy chain cDNA clone pSMHCZ, were compared to each other. It was found that the 3' untranslated regions as well as 482 nucleotides specifying the carboxyl coding region, were 100% homologous. Further examination revealed that the skeletal clone pSMHCZ diverges from the human cardiac beta myosin heavy chain cDNA clone pHMC3 at the 5' end. We present evidence in this report which indicates that the cardiac beta myosin heavy chain mRNA is expressed in skeletal muscle tissues. The human cardiac beta myosin heavy chain cDNA clone, pHMC3, which codes for a portion of the light meromyosin section of the myosin heavy chain, was used as a probe for S1 nuclease mapping studies with RNA derived from cardiac tissue, smooth muscle and skeletal muscle tissues consisting of fast-twitch, slow-twitch and mixed fast- and slow-twitch muscle fibres. Two probes were used to examine the expression of the mRNA. One probe (406 nucleotides) constitutes the 3' untranslated region and a portion of the coding region of the beta cardiac myosin heavy chain cDNA clone, which is 100% homologous to pSMHCZ, the skeletal cDNA clone. The other constitutes the majority of the coding region (1017 nucleotides) of the cardiac clone pHMC3 in which the first 216 nucleotides from the labelled end are 100% homologous to the skeletal clone pSMHCZ. In the soleus muscle, which is rich in slow-twitch type I muscle fibres, the expression of the cardiac beta myosin heavy chain mRNA was very prominent. In gastrocnemius muscle, a mixed fibre muscle, the expression of this mRNA was detected to a lesser degree than that for the soleus muscle. In vastus lateralis and vastus medialis, which consist of predominantly type II, fast-twitch fibres, there were trace amounts of the cardiac beta myosin heavy chain mRNA. When expression of this mRNA was tested in smooth muscle tissue none could be detected.
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PMID:Two different forms of beta myosin heavy chain are expressed in human striated muscle. 365 86

The expression of mRNAs for two cardiac myosins has been studied in the ventricles of hypo- and hyperthyroid rabbits by using cloned cDNA sequences corresponding to the mRNAs of the alpha- and beta-myosin heavy chains (HCs). The temporal change in relative levels of the alpha and beta HC mRNAs after triiodothyronine (T3) treatment of hypothyroid rabbits was determined by nuclease S1 mapping. In the hypothyroid state, only NC beta-mRNA was expressed in the ventricles. The HC alpha-mRNA was first detectable 4 h after administration of T3 (200 micrograms/kg) to hypothyroid animals. By 12, 24, and 72 h, HC alpha-mRNA represented 20, 50, and 90% of total myosin mRNA. The relationship between the relative mRNA levels and relative synthesis rates of myosin HCs was evaluated in 5- to 6-wk-old normal and thyrotoxic rabbits. Myosin synthesis rates were determined by labeling of protein in vivo with [2H]leucine. The V1 (HC alpha) and V3 (HC beta) isomyosins were separated by immune affinity chromatography and the HCs were isolated electrophoretically. In a normal euthyroid group of animals and in animals 12 and 24 h after administration of 200 micrograms of thyroxine, the relative mRNA levels and relative synthesis rates of the alpha and beta HCs were not significantly different. Our results show that, first, thyroid hormone causes a rapid accumulation of HC alpha-mRNA and loss of HC alpha-mRNA, and second, in normal and thyrotoxic rabbits, the relative synthesis rates of HC alpha and HC beta reflect the relative abundance of their respective mRNAs. These data are consistent with the thyroid hormones regulating synthesis of ventricular myosin at steps that precede translation of its message.
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PMID:Expression of myosin heavy chains during thyroid hormone-induced cardiac growth. 375 76

A cDNA clone, labeled pFOD5, isolated from a fetal-rat skeletal-muscle cDNA library, has been characterized and found to contain sequences corresponding to a perinatal-specific skeletal myosin heavy-chain (MHC) mRNA. This MHC cDNA demonstrates a high degree of nucleotide- and amino acid-sequence conservation with other MHC genes, but its carboxyl-terminal peptide and 3'-untranslated region are highly divergent and specific for this gene. S1 nuclease mapping experiments have shown that the perinatal MHC gene represented by this cDNA clone is only transiently expressed during skeletal-muscle development. Perinatal MHC mRNA is first detected late in fetal life, reaches maximal levels of expression at the end of the first postnatal week, and is de-induced thereafter. Its levels are almost undetectable at 28 days of postnatal life. During fetal and early postnatal life, the expression of this perinatal gene in skeletal muscle overlaps with the expression of the embryonic MHC gene. After the first week of extrauterine life, this gene is coexpressed with two adult MHC genes. The transient expression of this perinatal MHC gene raises interesting questions about the physiological significance of the MHC transitions and offers an interesting model for the study of MHC gene regulation.
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PMID:Characterization of a developmentally regulated perinatal myosin heavy-chain gene expressed in skeletal muscle. 614 24

Microinjection into an axon of an identified invertebrate neuron is shown to be a useful technique for analyzing the mechanisms of fast axonal transport. It permits direct assessment of the effect of agents that cannot permeate the plasma membrane on the translocation of material in the axon. The actin filament depolymerizer DNase I, when injected into the axon of the Aplysia neuron R2, caused a local block of fast transport of [3H]glycoprotein. Two agents that should interfere with the functioning of actin filaments without causing extensive depolymerization, tne N-ethylmaleimide-modified nuclease S1 fragment of myosin (injected) and dihydrocytochalasin B (applied externally). had no effect. Together these results suggest that actin plays a structural role in the axonal cytoskeleton rather than a role in transport force generation, the effect of DNase I being mediated by structural disordering of the axoplasm. Experiments were also done with inhibitors of dynein, the microtubule-associated ATPase. erythro-9-[3-(2-Hydroxynonyl)]adenine blocked transport but vanadate was ineffective.
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PMID:Microinjection into an identified axon to study the mechanism of fast axonal transport. 618 16

We have examined the expression of two embryonic myosin HC mRNAs using two cDNA clones (110 and 251) which we have previously constructed from RNA isolated from 14-day-old embryonic chick skeletal muscle. Sequence divergence in the 3' nontranslated regions enabled us to analyze the differential expression of the mRNAs corresponding to the two clones using the S1 nuclease mapping procedure. Clone 251 mRNA is expressed primarily in embryonic fast muscle, where its transcripts appear to be the predominant species. This mRNA is minimally expressed in the posthatching period, but it is not detected in adult leg and breast muscle. Messenger RNA for clone 110 is also primarily expressed in embryonic fast muscle. However, in the posthatching and adult stages of development, it continues to be expressed at a low level in leg muscle but not in breast muscle. The differential expression of these mRNAs during development strongly indicates that they correspond to two different genes coding for embryonic myosin HCs. Other myosin HC mRNAs which were partially homologous to the clone 110 or 251 mRNAs were also identified by S1 nuclease mapping. Using the probes from these two clones, a minimum of four other developmentally expressed forms were detected. Two of these correspond to "neonatal" myosin HCs, while the other two code for different adult myosin HCs present in leg and in breast muscle, respectively. The results therefore suggest a much greater diversity of myosin HC mRNAs expressed during development than previously reported.
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PMID:Cloned mRNA sequences for two types of embryonic myosin heavy chains from chick skeletal muscle. II. Expression during development using S1 nuclease mapping. 630 Jan 20


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