cAMP negatively regulates mRNA levels of actin and tropomyosin in rat cultured vascular smooth muscle cells.
The isoform expression patterns of actin and actin-binding proteins have been reported to be good markers for phenotypic modulation of rat vascular smooth muscle cells. In order to elucidate the regulatory mechanism of actin and tropomyosin isoform expression on a molecular basis, we examined the effects of various agents on the isoform expression patterns of actin and tropomyosin at the mRNA level in smooth muscle cells. We found that cAMP-elevating agents induced drastic decreases in the amounts of alpha-smooth muscle type actin and alpha-tropomyosin transcripts, the expression of other actin and tropomyosin isoforms being also repressed, but to a lesser extent. The results of the experiment involving RNA synthesis inhibitors strongly suggest that activation of some mRNA-specific degradation machinery by cAMP might be responsible at least for the rapid disappearance of alpha-smooth muscle type actin and alpha-tropomyosin transcripts in smooth muscle cells.
Ohara
O
O
Shionogi Research Laboratories, Osaka.
Nakano
T
T
Teraoka
H
H
Arita
H
H
D015056:1-Methyl-3-isobutylxanthine / Q000494:pharmacology; D000199:Actins / Q000096:biosynthesis*; D000818:Animals; D001483:Base Sequence; D003994:Bucladesine / Q000494:pharmacology; D002478:Cells, Cultured; D005576:Colforsin / Q000494:pharmacology; D016384:Consensus Sequence; D000242:Cyclic AMP / Q000502:physiology*; D003609:Dactinomycin / Q000494:pharmacology; D015151:Immunoblotting; D008297:Male; D008969:Molecular Sequence Data; D009131:Muscle, Smooth, Vascular / Q000166:cytology / Q000378:metabolism*; D009841:Oligonucleotides / Q000032:analysis; D010641:Phenotype; D012333:RNA, Messenger / Q000096:biosynthesis / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains; D014335:Tropomyosin / Q000096:biosynthesis*
D000199:Actins; D009841:Oligonucleotides; D012333:RNA, Messenger; D014335:Tropomyosin; D003609:Dactinomycin; D005576:Colforsin; D003994:Bucladesine; D000242:Cyclic AMP; D015056:1-Methyl-3-isobutylxanthine