scholarly journals Sequential activation of alpha-actin genes during avian cardiogenesis: vascular smooth muscle alpha-actin gene transcripts mark the onset of cardiomyocyte differentiation.

1988 ◽  
Vol 107 (6) ◽  
pp. 2575-2586 ◽  
Author(s):  
D L Ruzicka ◽  
R J Schwartz
Keyword(s):  
Smooth Muscle ◽  
Vascular Smooth Muscle ◽  
Cardiac Cells ◽  
Actin Gene ◽  
Heart Tube ◽  
Specific Expression ◽  
Actin Genes ◽  
Beta Actin ◽  
Smooth Muscle Alpha Actin ◽  
Alpha Actin

The expression of cytoplasmic beta-actin and cardiac, skeletal, and smooth muscle alpha-actins during early avian cardiogenesis was analyzed by in situ hybridization with mRNA-specific single-stranded DNA probes. The cytoplasmic beta-actin gene was ubiquitously expressed in the early chicken embryo. In contrast, the alpha-actin genes were sequentially activated in avian cardiac tissue during the early stages of heart tube formation. The accumulation of large quantities of smooth muscle alpha-actin transcripts in epimyocardial cells preceded the expression of the sarcomeric alpha-actin genes. The accumulation of skeletal alpha-actin mRNAs in the developing heart lagged behind that of cardiac alpha-actin by several embryonic stages. At Hamburger-Hamilton stage 12, the smooth muscle alpha-actin gene was selectively down-regulated in the heart such that only the conus, which subsequently participates in the formation of the vascular trunks, continued to express this gene. This modulation in smooth muscle alpha-actin gene expression correlated with the beginning of coexpression of sarcomeric alpha-actin transcripts in the epimyocardium and the onset of circulation in the embryo. The specific expression of the vascular smooth muscle alpha-actin gene marks the onset of differentiation of cardiac cells and represents the first demonstration of coexpression of both smooth muscle and striated alpha-actin genes within myogenic cells.

scholarly journals The vascular smooth muscle alpha-actin gene is reactivated during cardiac hypertrophy provoked by load.

1991 ◽  
Vol 88 (5) ◽  
pp. 1581-1588 ◽  
Author(s):  
F M Black ◽  
S E Packer ◽  
T G Parker ◽  
L H Michael ◽  
R Roberts ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Vascular Smooth Muscle ◽  
Cardiac Hypertrophy ◽  
Actin Gene ◽  
Smooth Muscle Alpha Actin ◽  
Alpha Actin

scholarly journals The complete sequence of the mouse skeletal alpha-actin gene reveals several conserved and inverted repeat sequences outside of the protein-coding region.

1986 ◽  
Vol 6 (1) ◽  
pp. 15-25 ◽  
Author(s):  
M C Hu ◽  
S B Sharp ◽  
N Davidson
Keyword(s):  
Amino Acids ◽  
Nucleotide Sequence ◽  
Inverted Repeat ◽  
Actin Gene ◽  
Coding Region ◽  
Specific Expression ◽  
Protein Coding ◽  
Repeat Sequences ◽  
Actin Genes ◽  
Alpha Actin

The complete nucleotide sequence of a genomic clone encoding the mouse skeletal alpha-actin gene has been determined. This single-copy gene codes for a protein identical in primary sequence to the rabbit skeletal alpha-actin. It has a large intron in the 5'-untranslated region 12 nucleotides upstream from the initiator ATG and five small introns in the coding region at codons specifying amino acids 41/42, 150, 204, 267, and 327/328. These intron positions are identical to those for the corresponding genes of chickens and rats. Similar to other skeletal alpha-actin genes, the nucleotide sequence codes for two amino acids, Met-Cys, preceding the known N-terminal Asp of the mature protein. Comparison of the nucleotide sequences of rat, mouse, chicken, and human skeletal muscle alpha-actin genes reveals conserved sequences (some not previously noted) outside of the protein-coding region. Furthermore, several inverted repeat sequences, partially within these conserved regions, have been identified. These sequences are not present in the vertebrate cytoskeletal beta-actin genes. The strong conservation of the inverted repeat sequences suggests that they may have a role in the tissue-specific expression of skeletal alpha-actin genes.

scholarly journals Negative regulation of the vascular smooth muscle alpha-actin gene in fibroblasts and myoblasts: disruption of enhancer function by sequence-specific single-stranded-DNA-binding proteins.

1995 ◽  
Vol 15 (5) ◽  
pp. 2429-2436 ◽  
Author(s):  
S Sun ◽  
E S Stoflet ◽  
J G Cogan ◽  
A R Strauch ◽  
M J Getz
Keyword(s):  
Smooth Muscle ◽  
Dna Binding ◽  
Vascular Smooth Muscle ◽  
Binding Site ◽  
Binding Activity ◽  
Actin Gene ◽  
Single Stranded Dna ◽  
Dna Binding Activity ◽  
Double Stranded Dna ◽  
Alpha Actin

Transcriptional activation and repression of the vascular smooth muscle (VSM) alpha-actin gene in myoblasts and fibroblasts is mediated, in part, by positive and negative elements contained within an approximately 30-bp polypurine-polypyrimidine tract. This region contains binding sites for an essential transcription-activating protein, identified as transcriptional enhancer factor I (TEF-1), and two tissue-restrictive, sequence-specific, single-stranded-DNA-binding activities termed VACssBF1 and VACssBF2. TEF-1 has no detectable single-stranded-DNA-binding activity, while VACssBF1 and VACssBF2 have little, if any, affinity for double-stranded DNA. Site-specific mutagenesis experiments demonstrate that the determinants of VACssBF1 and VACssBF2 binding lie on opposite strands of the DNA helix and include the TEF-1 recognition sequence. Functional analysis of this region reveals that the CCAAT box-binding protein nuclear factor Y (NF-Y) can substitute for TEF-1 in activating VSM alpha-actin transcription but that the TEF-1-binding site is essential for the maintenance of full transcriptional repression. Importantly, replacement of the TEF-1-binding site with that for NF-Y diminishes the ability of VACssBF1 and VACssBF2 to bind to separated single strands. Additional activating mutations have been identified which lie outside of the TEF-1-binding site but which also impair single-stranded-DNA-binding activity. These data support a model in which VACssBF1 and VACssBF2 function as repressors of VSM alpha-actin transcription by stabilizing a local single-stranded-DNA conformation, thus precluding double-stranded-DNA binding by the essential transcriptional activator TEF-1.

Oxygen modulates alpha 1B-adrenergic receptor gene expression by arterial but not venous vascular smooth muscle

1996 ◽  
Vol 271 (4) ◽  
pp. H1599-H1608 ◽  
Author(s):  
A. D. Eckhart ◽  
Z. Zhu ◽  
W. J. Arendshorst ◽  
J. E. Faber
Keyword(s):  
Gene Expression ◽  
Smooth Muscle ◽  
Vascular Smooth Muscle ◽  
In Vivo Models ◽  
Beta Actin ◽  
Actin Mrna ◽  
Alpha Actin

Blood and tissue O2 levels are major determinants of short-term autoregulatory adjustments in vascular smooth muscle cell (SMC) tension and may effect long-term alterations in SMC catecholamine responsiveness. We examined the hypothesis that prolonged hypoxia altered gene expression of alpha 1-adrenoceptors. After exposure of cultured aortic (in vitro) SMC to 3% O2 for 8 h, alpha 1B mRNA increased to 523% (P = 0.02) of control cells (21% O2) and to 205% (P = 0.04) in in situ organ-cultured aortic SMC. In vivo hypoxic hypoxia (10% inspired O2) similarly increased aortic SMC alpha 1B mRNA 180% (P = 0.02). In contrast, alpha 1D, alpha-actin and beta-actin mRNA levels were not changed in aortic SMC by low O2 in the in vitro, in situ, or in vivo models. Unlike aortic SMC, vena caval SMC alpha 1B mRNA expression did not change with low-O2 exposure in vitro or in vivo, nor did alpha 1D, alpha-actin or beta-actin mRNA. Aortic SMC alpha 1B transcription rate increased 360% (P = 0.02), whereas alpha 1D, alpha-actin, and beta-actin transcription was unchanged. Neither alpha 1B nor alpha 1D mRNA stability was altered by low-O2 exposure. Total alpha 1-adrenoceptor density ([3H]prazosin binding) increased 12% (P = 0.04) after 24 h of 3% O2. This was associated with a 200% increase (P < 0.01) in the chloroethylclonidine (CEC)-sensitive alpha 1-adrenoceptor population and no change in CEC-insensitive alpha 1-adrenoceptor density. Exposure of aortic SMC to 24 h of 3% O2 increased the maximum response of norepinephrine-evoked elevations in intracellular Ca2+ as measured using fura 2. Low O2 did not change responses to another G protein-coupled receptor, angiotensin II. These data suggest that reduced O2, during prolonged hypoxemia or tissue ischemia, may selectively increase expression of functionally coupled alpha 1B-adrenoceptors in arterial blood vessels.

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