cDNA cloning of a myosin heavy chain isoform in embryonic smooth muscle and its expression during vascular development and in arteriosclerosis.

Makoto Kuro-o, Ryozo Nagai, Ken Ichi Nakahara, Hirohisa Katoh, Rong Chi Tsai, Hidetsugu Tsuchimochi, Yoshio Yazaki, Akiyuki Ohkubo, Fumimaro Takaku

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Abstract

Adult rabbit smooth muscles contain two types of myosin heavy chain (MHC) isoforms, SM1 and SM2, which are generated through alternative RNA splicing from a single gene (Nagai, R., Kuro-o, M., Babij, P. and Periasamy, M. (1989) J. Biol. Chem. 264, 9734-9737). We previously reported that the expression of SM1 and SM2 during vascular development is differentially regulated at the level of RNA splicing, whereby SM1 is constitutively expressed from early development but SM2 appear after birth (Kuro-o, M., Nagai, R., Tsuchimochi, H., Katoh, H., Yazaki, Y., Ohkubo, A. and Takaku, F. (1989) J. Biol. Chem. 264, 18272-18275). We also demonstrated that embryonic vascular smooth muscles contain a third type of MHC isoform, referred to as SMemb in this report, which comigrates on sodium dodecyl sulfate-polyacrylamide gel electrophoresis with SM2. In the present study we have isolated and characterized a cDNA clone (FSMHC34) for SMemb. FSMHC34 encodes the light meromyosin region including the carboxyl terminus and showed 70% amino acid sequence identity with SM1 or SM2. SMemb is a nonmuscle-type MHC and identical with brain MHC, but clearly distinct from 196-kDa nonmuscle MHC in cultured smooth muscle cells. The expression of SMemb was predominant in embryonic and perinatal aortas, but down-regulated with vascular development. Interestingly SMemb was reexpressed in proliferating smooth muscle cells of arteriosclerotic neointimas. These results suggest that smooth muscle proliferation is coupled to the expression of SMemb and that dedifferentiation of smooth muscles toward the embryonic phenotype is involved in the mechanisms underlying atherosclerosis.

Original languageEnglish (US)
Pages (from-to)3768-3773
Number of pages6
JournalJournal of Biological Chemistry
Volume266
Issue number6
StatePublished - Jul 17 1991

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ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

Cite this

Kuro-o, M., Nagai, R., Nakahara, K. I., Katoh, H., Tsai, R. C., Tsuchimochi, H., Yazaki, Y., Ohkubo, A., & Takaku, F. (1991). cDNA cloning of a myosin heavy chain isoform in embryonic smooth muscle and its expression during vascular development and in arteriosclerosis. Journal of Biological Chemistry, 266(6), 3768-3773.