A novel tropomyosin isoform encoded by the Xenopus laevis alpha-TM gene is expressed in the brain

作者：Gaillard C; Theze N; Lerivray H; Hardy S; Lepetit D; Thiebaud P^*

来源：Gene, 1998, 207(2): 235-239.

DOI：10.1016/S0378-1119(97)00634-3

• nucleotide sequence
• expression
• isoform diversity
• gene organization
• amphibian

A full-length cDNA clone encoding a novel non-muscle tropomyosin (nmTM) termed X alpha TMB5, as yet unidentified in vertebrates, was isolated from a Xenopus laevis (XI) brain cDNA library. X alpha TMB5 is derived from the XL alpha-tropomyosin gene (X alpha TM), which was previously found to express striated muscle and nmTM isoforms via an alternative splicing mechanism. The deduced amino-acid sequence reveals that X alpha TMB5 contains 248 amino acids. The protein differs from the skeletal muscle alpha-TM isoform only at its NH2-terminal region. The mRNA encoding X alpha TMB5 is expressed mainly in brain and striated muscle. Genomic clone analysis reveals that, unlike mammals and avian, the X alpha TM gene is devoid of the brain-specific exon 9c. The amphibian alpha-TM gene is a complex transcription unit containing 14 exons, including two alternative promoters, two internal mutually exclusive exons, and two alternatively spliced 3' exons that encode two different COOH-terminal coding regions. Therefore, a total of at least five distinct mRNAs are expressed from the X alpha TM gene in a cell-type-specific manner.

• 出版日期1998-1-30