An amphibian cytoskeletal-type actin gene is expressed exclusively in muscle tissue

Development ◽  
1987 ◽  
Vol 101 (2) ◽  
pp. 393-402 ◽  
Author(s):  
T.J. Mohun ◽  
N. Garrett
Keyword(s):  
Nucleotide Sequence ◽  
Protein Isoforms ◽  
Actin Gene ◽  
Promoter Regions ◽  
Conserved Sequence ◽  
Beta Actin ◽  
Genes Encoding ◽  
Actin Mrna ◽  
Ccaat Box ◽  
Equivalent Region

The complete nucleotide sequence of two Xenopus actin genes encoding cytoskeletal protein isoforms has been determined. Transcripts from these genes are remarkably similar in nucleotide sequence throughout their length and code for type-5 and type-8 cytoskeletal actins. Both share some sequence homology with human gamma-actin mRNA within the 3′ untranslated region but none with the equivalent region of any vertebrate beta-actin transcript. The promoter regions of the two Xenopus genes are virtually identical from the cap site to the CCAAT box and show extensive homology further upstream. Despite such similarity, the two genes are divergently expressed during embryonic development. The type-5 actin gene is expressed in all regions of the developing embryo whilst the type-8 gene is coregulated with the muscle-specific skeletal actin gene. In common with mammalian and avian cytoskeletal actin counterparts, the Xenopus genes possess a conserved sequence within their promoter that has previously been identified as a transcription-factor-binding site.

Novel chicken actin gene: third cytoplasmic isoform

1985 ◽  
Vol 5 (5) ◽  
pp. 1151-1162
Author(s):  
D J Bergsma ◽  
K S Chang ◽  
R J Schwartz
Keyword(s):  
Nucleotide Sequence ◽  
Single Copy ◽  
Actin Gene ◽  
Single Copy Gene ◽  
Gene Diversification ◽  
Mrna Transcripts ◽  
Copy Gene ◽  
Actin Mrna ◽  
Distinct Member ◽  
Actin Protein

We identified a novel chicken actin gene. The actin protein deduced from its nucleotide sequence very closely resembles the vertebrate cytoplasmic actins; accordingly, we classified this gene as a nonmuscle type. We adopted the convention for indicating the nonmuscle actins of the class Amphibia (Vandekerckhove et al., J. Mol. Biol. 152:413-426) and denoted this gene as type 5. RNA blot analysis demonstrated that the type 5 actin mRNA transcripts accumulate in adult tissues in a pattern indicative of a nonmuscle actin gene. Genomic DNA blots indicated that the type 5 actin is a single copy gene and a distinct member of the chicken actin multigene family. Inspection of the nucleotide sequence revealed many features that distinguished the type 5 gene from all other vertebrate actin genes examined to date. These unique characteristics include: (i) an initiation Met codon preceding an Ala codon, a feature previously known only in plant actins, (ii) a single intron within the 5' untranslated region, with no interruptions in the coding portion of the gene, and (iii) an atypical Goldberg-Hogness box (ATAGAA) preceding the mRNA initiation terminus. These unusual features have interesting implications for actin gene diversification during evolution.

Molecular cloning and characterization of mutant and wild-type human beta-actin genes

1984 ◽  
Vol 4 (10) ◽  
pp. 1961-1969
Author(s):  
J Leavitt ◽  
P Gunning ◽  
P Porreca ◽  
S Y Ng ◽  
C S Lin ◽  
...  
Keyword(s):  
Homologous Recombination ◽  
Human Fibroblasts ◽  
Actin Gene ◽  
Actin Genes ◽  
Beta Actin ◽  
Gene Libraries ◽  
Actin Mrna ◽  
Dna Fragment ◽  
Specific Sequences

There are more than 20 beta-actin-specific sequences in the human genome, many of which are pseudogenes. To facilitate the isolation of potentially functional beta-actin genes, we used the new method of B. Seed (Nucleic Acids Res. 11:2427-2446, 1983) for selecting genomic clones by homologous recombination. A derivative of the pi VX miniplasmid, pi AN7 beta 1, was constructed by insertion of the 600-base-pair 3' untranslated region of the beta-actin mRNA expressed in human fibroblasts. Five clones containing beta-actin sequences were selected from an amplified human fetal gene library by homologous recombination between library phage and the miniplasmid. One of these clones contained a complete beta-actin gene with a coding sequence identical to that determined for the mRNA of human fibroblasts. A DNA fragment consisting of mostly intervening sequences from this gene was then used to identify 13 independent recombinant copies of the analogous gene from two specially constructed gene libraries, each containing one of the two types of mutant beta-actin genes found in a line of neoplastic human fibroblasts. The amino acid and nucleotide sequences encoded by the unmutated gene predict that a guanine-to-adenine transition is responsible for the glycine-to-aspartic acid mutation at codon 244 and would also result in the loss of a HaeIII site. Detection of this HaeIII polymorphism among the fibroblast-derived clones verified the identity of the beta-actin gene expressed in human fibroblasts.

scholarly journals Transfection of nonmuscle beta- and gamma-actin genes into myoblasts elicits different feedback regulatory responses from endogenous actin genes

1992 ◽  
Vol 117 (4) ◽  
pp. 787-797 ◽  
Author(s):  
C Lloyd ◽  
G Schevzov ◽  
P Gunning
Keyword(s):  
Actin Cytoskeleton ◽  
Feedback Regulation ◽  
Cytochalasin D ◽  
Actin Gene ◽  
Down Regulation ◽  
Actin Genes ◽  
Beta Actin ◽  
Actin Mrna ◽  
Actin Protein

We have examined the role of feedback-regulation in the expression of the nonmuscle actin genes. C2 mouse myoblasts were transfected with the human beta- and gamma-actin genes. In gamma-actin transfectants we found that the total actin mRNA and protein pools remained unchanged. Increasing levels of human gamma-actin expression resulted in a progressive down-regulation of mouse beta- and gamma-actin mRNAs. Transfection of the beta-actin gene resulted in an increase in the total actin mRNA and protein pools and induced an increase in the levels of mouse beta-actin mRNA. In contrast, transfection of a beta-actin gene carrying a single-point mutation (beta sm) produced a feedback-regulatory response similar to that of the gamma-actin gene. Expression of a beta-actin gene encoding an unstable actin protein had no impact on the endogenous mouse actin genes. This suggests that the nature of the encoded actin protein determines the feedback-regulatory response of the mouse genes. The role of the actin cytoskeleton in mediating this feedback-regulation was evaluated by disruption of the actin network with Cytochalasin D. We found that treatment with Cytochalasin D abolished the down-regulation of mouse gamma-actin in both the gamma- and beta sm-actin transfectants. In contrast, a similar level of increase was observed for the mouse beta-actin mRNA in both control and transfected cells. These experiments suggest that the down-regulation of mouse gamma-actin mRNA is dependent on the organization of the actin cytoskeleton. In addition, the mechanism responsible for the down-regulation of beta-actin may be distinct from that governing gamma-actin. We conclude that actin feedback-regulation provides a biochemical assay for differences between the two nonmuscle actin genes.

scholarly journals Cellular localization of muscle and nonmuscle actin mRNAs in chicken primary myogenic cultures: the induction of alpha-skeletal actin mRNA is regulated independently of alpha-cardiac actin gene expression.

1988 ◽  
Vol 106 (6) ◽  
pp. 2077-2086 ◽  
Author(s):  
L J Hayward ◽  
Y Y Zhu ◽  
R J Schwartz
Keyword(s):  
Cellular Localization ◽  
Myoblast Fusion ◽  
Bipolar Cells ◽  
Gene Probe ◽  
Actin Gene ◽  
Cardiac Actin ◽  
Beta Actin ◽  
Hybridization Probes ◽  
Muscle Cultures ◽  
Actin Mrna

Specific DNA fragments complementary to the 3' untranslated regions of the beta-, alpha-cardiac, and alpha-skeletal actin mRNAs were used as in situ hybridization probes to examine differential expression and distribution of these mRNAs in primary myogenic cultures. We demonstrated that prefusion bipolar-shaped cells derived from day 3 dissociated embryonic somites were equivalent to myoblasts derived from embryonic day 11-12 pectoral tissue with respect to the expression of the alpha-cardiac actin gene. Fibroblasts present in primary muscle cultures were not labeled by the alpha-cardiac actin gene probe. Since virtually all of the bipolar cells express alpha-cardiac actin mRNA before fusion, we suggest that the bipolar phenotype may distinguish a committed myogenic cell type. In contrast, alpha-skeletal actin mRNA accumulates only in multinucleated myotubes and appears to be regulated independently from the alpha-cardiac actin gene. Accumulation of alpha-skeletal but not alpha-cardiac actin mRNA can be blocked by growth in Ca2+-deficient medium which arrests myoblast fusion. Thus, the sequential appearance of alpha-cardiac and then alpha-skeletal actin mRNA may result from factors that arise during terminal differentiation. Finally, the beta-actin mRNA was located in both fibroblasts and myoblasts but diminished in content during myoblast fusion and was absent from differentiated myotubes. It appears that in primary myogenic cultures, an asynchronous stage-dependent induction of two different alpha-striated actin mRNA species occurs concomitant with the deinduction of the nonmuscle beta-actin gene.

Expression of transfected mutant beta-actin genes: transitions toward the stable tumorigenic state

1987 ◽  
Vol 7 (7) ◽  
pp. 2467-2476
Author(s):  
J Leavitt ◽  
S Y Ng ◽  
M Varma ◽  
G Latter ◽  
S Burbeck ◽  
...  
Keyword(s):  
Human Fibroblasts ◽  
Actin Gene ◽  
Wild Type ◽  
Transfected Cells ◽  
Actin Genes ◽  
Beta Actin ◽  
Normal Human ◽  
Actin Mrna ◽  
Elevated Rate ◽  
Actin Expression

Mutant human beta-actin genes were introduced into normal human (KD) fibroblasts and the derivative cell line HuT-12, which is immortalized but nontumorigenic, to test their ability to promote conversion to the tumorigenic state. Transfected substrains of HuT-12 fibroblasts that expressed abundant levels of mutant beta-actin (Gly-244----Asp-244) produced subcutaneous tumors in athymic mice after long latent periods (1.5 to 3 months). However, transfected substrains of KD fibroblasts retained their normal finite life span in culture and consequently were incapable of producing tumors. Substrains of HuT-12 cells transfected with the wild-type beta-actin gene and some transfected strains that expressed low or undetectable levels of mutant beta-actin did not produce tumors. Cell lines derived from transfectant cell tumors always exhibited elevated synthesis of the mutant beta-actin, ranging from 145 to 476% of the level expressed by the transfected cells that were inoculated to form the tumor. In general, primary transfectant cells that expressed the highest levels of mutant beta-actin were more tumorigenic than strains that expressed lower levels. The tumor-derived strains were stable in tumorigenicity and produced tumors with shortened latent periods of only 2 to 4 weeks. These findings imply that the primary transfectant strains develop subpopulations of cells that are selected to form tumors because of their elevated rate of exogenous mutant beta-actin synthesis. Actin synthesis and accumulation of gamma-actin mRNA from the endogenous beta- and gamma-actin genes were diminished in tumor-derived strains, apparently to compensate for elevated mutant beta-actin synthesis and maintain the normal cellular concentration of actin. Synthesis of the transformation-sensitive tropomyosin isoforms was decreased along with mutant beta-actin expression. Such modulations in tropomyosin synthesis are characteristically seen in transformation of avian, rodent, and human fibroblasts. Our results suggest that this mutant beta-actin contributes to the neoplastic phenotype of immortalized human fibroblasts by imposing a cytoarchitectural defect and inducing abnormal expression of cytoskeletal tropomyosins.

scholarly journals Molecular cloning and characterization of mutant and wild-type human beta-actin genes.

1984 ◽  
Vol 4 (10) ◽  
pp. 1961-1969 ◽  
Author(s):  
J Leavitt ◽  
P Gunning ◽  
P Porreca ◽  
S Y Ng ◽  
C S Lin ◽  
...  
Keyword(s):  
Homologous Recombination ◽  
Human Fibroblasts ◽  
Actin Gene ◽  
Actin Genes ◽  
Beta Actin ◽  
Gene Libraries ◽  
Actin Mrna ◽  
Dna Fragment ◽  
Specific Sequences

There are more than 20 beta-actin-specific sequences in the human genome, many of which are pseudogenes. To facilitate the isolation of potentially functional beta-actin genes, we used the new method of B. Seed (Nucleic Acids Res. 11:2427-2446, 1983) for selecting genomic clones by homologous recombination. A derivative of the pi VX miniplasmid, pi AN7 beta 1, was constructed by insertion of the 600-base-pair 3' untranslated region of the beta-actin mRNA expressed in human fibroblasts. Five clones containing beta-actin sequences were selected from an amplified human fetal gene library by homologous recombination between library phage and the miniplasmid. One of these clones contained a complete beta-actin gene with a coding sequence identical to that determined for the mRNA of human fibroblasts. A DNA fragment consisting of mostly intervening sequences from this gene was then used to identify 13 independent recombinant copies of the analogous gene from two specially constructed gene libraries, each containing one of the two types of mutant beta-actin genes found in a line of neoplastic human fibroblasts. The amino acid and nucleotide sequences encoded by the unmutated gene predict that a guanine-to-adenine transition is responsible for the glycine-to-aspartic acid mutation at codon 244 and would also result in the loss of a HaeIII site. Detection of this HaeIII polymorphism among the fibroblast-derived clones verified the identity of the beta-actin gene expressed in human fibroblasts.

scholarly journals Expression of transfected mutant beta-actin genes: transitions toward the stable tumorigenic state.

1987 ◽  
Vol 7 (7) ◽  
pp. 2467-2476 ◽  
Author(s):  
J Leavitt ◽  
S Y Ng ◽  
M Varma ◽  
G Latter ◽  
S Burbeck ◽  
...  
Keyword(s):  
Human Fibroblasts ◽  
Actin Gene ◽  
Wild Type ◽  
Transfected Cells ◽  
Actin Genes ◽  
Beta Actin ◽  
Normal Human ◽  
Actin Mrna ◽  
Elevated Rate ◽  
Actin Expression

Mutant human beta-actin genes were introduced into normal human (KD) fibroblasts and the derivative cell line HuT-12, which is immortalized but nontumorigenic, to test their ability to promote conversion to the tumorigenic state. Transfected substrains of HuT-12 fibroblasts that expressed abundant levels of mutant beta-actin (Gly-244----Asp-244) produced subcutaneous tumors in athymic mice after long latent periods (1.5 to 3 months). However, transfected substrains of KD fibroblasts retained their normal finite life span in culture and consequently were incapable of producing tumors. Substrains of HuT-12 cells transfected with the wild-type beta-actin gene and some transfected strains that expressed low or undetectable levels of mutant beta-actin did not produce tumors. Cell lines derived from transfectant cell tumors always exhibited elevated synthesis of the mutant beta-actin, ranging from 145 to 476% of the level expressed by the transfected cells that were inoculated to form the tumor. In general, primary transfectant cells that expressed the highest levels of mutant beta-actin were more tumorigenic than strains that expressed lower levels. The tumor-derived strains were stable in tumorigenicity and produced tumors with shortened latent periods of only 2 to 4 weeks. These findings imply that the primary transfectant strains develop subpopulations of cells that are selected to form tumors because of their elevated rate of exogenous mutant beta-actin synthesis. Actin synthesis and accumulation of gamma-actin mRNA from the endogenous beta- and gamma-actin genes were diminished in tumor-derived strains, apparently to compensate for elevated mutant beta-actin synthesis and maintain the normal cellular concentration of actin. Synthesis of the transformation-sensitive tropomyosin isoforms was decreased along with mutant beta-actin expression. Such modulations in tropomyosin synthesis are characteristically seen in transformation of avian, rodent, and human fibroblasts. Our results suggest that this mutant beta-actin contributes to the neoplastic phenotype of immortalized human fibroblasts by imposing a cytoarchitectural defect and inducing abnormal expression of cytoskeletal tropomyosins.

scholarly journals Novel chicken actin gene: third cytoplasmic isoform.

1985 ◽  
Vol 5 (5) ◽  
pp. 1151-1162 ◽  
Author(s):  
D J Bergsma ◽  
K S Chang ◽  
R J Schwartz
Keyword(s):  
Nucleotide Sequence ◽  
Single Copy ◽  
Actin Gene ◽  
Single Copy Gene ◽  
Gene Diversification ◽  
Mrna Transcripts ◽  
Copy Gene ◽  
Actin Mrna ◽  
Distinct Member ◽  
Actin Protein

We identified a novel chicken actin gene. The actin protein deduced from its nucleotide sequence very closely resembles the vertebrate cytoplasmic actins; accordingly, we classified this gene as a nonmuscle type. We adopted the convention for indicating the nonmuscle actins of the class Amphibia (Vandekerckhove et al., J. Mol. Biol. 152:413-426) and denoted this gene as type 5. RNA blot analysis demonstrated that the type 5 actin mRNA transcripts accumulate in adult tissues in a pattern indicative of a nonmuscle actin gene. Genomic DNA blots indicated that the type 5 actin is a single copy gene and a distinct member of the chicken actin multigene family. Inspection of the nucleotide sequence revealed many features that distinguished the type 5 gene from all other vertebrate actin genes examined to date. These unique characteristics include: (i) an initiation Met codon preceding an Ala codon, a feature previously known only in plant actins, (ii) a single intron within the 5' untranslated region, with no interruptions in the coding portion of the gene, and (iii) an atypical Goldberg-Hogness box (ATAGAA) preceding the mRNA initiation terminus. These unusual features have interesting implications for actin gene diversification during evolution.

scholarly journals Microarray-Based Identification of a NovelStreptococcus pneumoniae Regulon Controlled by an Autoinduced Peptide

2000 ◽  
Vol 182 (17) ◽  
pp. 4696-4703 ◽  
Author(s):  
Antoine de Saizieu ◽  
Christophe Gardès ◽  
Nicholas Flint ◽  
Christian Wagner ◽  
Markus Kamber ◽  
...  
Keyword(s):  
Response Regulator ◽  
Open Reading Frames ◽  
Leader Peptide ◽  
Recognition Sequence ◽  
Promoter Regions ◽  
Sequence Element ◽  
Conserved Sequence ◽  
Insertional Inactivation ◽  
Genes Encoding ◽  
Processed Form

ABSTRACT We have identified in the Streptococcus pneumoniaegenome sequence a two-component system (TCS13, Blp [bacteriocin-like peptide]) which is closely related to quorum-sensing systems regulating cell density-dependent phenotypes such as the development of genetic competence or the production of antimicrobial peptides in lactic acid bacteria. In this study we present evidence that TCS13 is a peptide-sensing system that controls a regulon including genes encoding Blps. Downstream of the Blp TCS (BlpH R) we identified open reading frames (blpAB) that have the potential to encode an ABC transporter that is homologous to the ComA/B export system for the competence-stimulating peptide ComC. The putative translation product of blpC, a small gene located downstream ofblpAB, has a leader peptide with a Gly-Gly motif. This leader peptide is typical of precursors processed by this family of transporters. Microarray-based expression profiling showed that a synthetic oligopeptide corresponding to the processed form of BlpC (BlpC*) induces a distinct set of 16 genes. The changes in the expression profile elicited by synthetic BlpC* depend on BlpH since insertional inactivation of its corresponding gene abolishes differential gene induction. Comparison of the promoter regions of theblp genes disclosed a conserved sequence element formed by two imperfect direct repeats upstream of extended −10 promoter elements. We propose that BlpH is the sensor for BlpC* and the conserved sequence element is a recognition sequence for the BlpR response regulator.

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