Alternative splicing of a single exon causes a major impact on the affinity of tropomyosin isoforms for actin filaments.

Tropomyosin is generally known as an actin-binding protein that regulates actomyosin interaction and actin filament stability. In metazoans, multiple tropomyosin isoforms are expressed, and some of them are involved in generating subpopulations of actin cytoskeleton in an isoform-specific manner. However, functions of many tropomyosin isoforms remain unknown.

m A-mediated alternative splicing coupled with nonsense-mediated mRNA decay regulates SAM synthetase homeostasis.

Alternative splicing of pre-mRNAs can regulate gene expression levels by coupling with nonsense-mediated mRNA decay (NMD). In order to elucidate a repertoire of mRNAs regulated by alternative splicing coupled with NMD (AS-NMD) in an organism, we performed long-read RNA sequencing of poly(A) RNAs from an NMD-deficient mutant strain of Caenorhabditis elegans, and obtained full-length sequences for mRNA isoforms from 259 high-confidence AS-NMD genes. Among them are the S-adenosyl-L-methionine (SAM) synthetase (sams) genes sams-3 and sams-4.

Alternative splicing of the Caenorhabditis elegans lev-11 tropomyosin gene is regulated in a tissue-specific manner.

Tropomyosin isoforms contribute to generation of functionally divergent actin filaments. In the nematode Caenorhabditis elegans, multiple isoforms are produced from lev-11, the single tropomyosin gene, by combination of two separate promoters and alternative pre-mRNA splicing. In this study, we report that alternative splicing of lev-11 is regulated in a tissue-specific manner so that a particular tropomyosin isoform is expressed in each tissue.

Tropomyosin isoforms differentially affect muscle contractility in the head and body regions of the nematode Caenorhabditis elegans.

Tropomyosin, one of the major actin filament-binding proteins, regulates actin-myosin interaction and actin-filament stability. Multicellular organisms express a number of tropomyosin isoforms, but understanding of isoform-specific tropomyosin functions is incomplete. The nematode Caenorhabditis elegans has a single tropomyosin gene, lev-11, which has been reported to express four isoforms by using two separate promoters and alternative splicing.