Human hTM alpha gene: expression in muscle and nonmuscle tissue.

Abstract

We have isolated a cDNA clone from a human skeletal muscle library which contains the complete protein-coding sequence of a skeletal muscle a-tropomyosin. This cDNA sequence defines a fourth human tropomyosin gene, the hTMa gene, which is distinct from the hTMnm gene encoding a closely related isoform of skeletal muscle a-tropomyosin. In cultured human fibroblasts, the hTMa gene encodes both skeletal-muscleand smooth-muscle-type a-tropomyosins by using an alternative mRNA-splicing mechanism.

Plasticity in adipogenesis and osteogenesis of human mesenchymal stem cells

“…The reverse regulation pattern of down regulated non-adipogenic gene products (e.g. jagged 1, JAG1 correlated with osteogenesis (Nobta et al, 2005) and angiogenesis (Uyttendaele et al, 2000), CYR61 involved in angiogenesis (Lau and Lam, 1999;Schutze et al, 2005a), muscle-associated tropomyosin 1 (alpha), cysteine and glycine-rich protein 2, CSRP2, myosin heavy polypeptide 11 smooth muscle, and villin 2 A c c e p t e d M a n u s c r i p t -17 -(ezrin), VIL2 (MacLeod and Gooding, 1988;Louis et al, 1997;Babu et al, 2000;Moyen et al, 2004)) and up regulated adipogenesis-related gene products (C/EBPα, LPL and acetyl-CoA carboxylase β (Rosen et al, 2002;Wu et al, 1999;Fried et al, 1993;Spiegelman et al, 1993), and two glucose transporter molecules SLC2A3 and SLC2A14) could contribute to the switch of preosteoblasts into adipocytes during transdifferentiation. Furthermore, the initiation of transdifferentiation could involve other factors and signaling pathways that have not been described in the context of direct differentiation or whose functions have not been revealed so far.…”

Three novel brain tropomyosin isoforms are expressed from the rat alpha-tropomyosin gene through the use of alternative promoters and alternative RNA processing.

“…The polyadenylation site used in exon 9b in brain mRNA is located 77 nt upstream of the polyadenylation site used in skeletal muscle a-tropomyosin mRNA. It is also of interest to note that the human skeletal muscle a-tropomyosin message conserves the equivalent exon 9b coding sequence in its 3'-untranslated region (40 10,1990 on 30,36,[40][41][42]54). The most complex of the vertebrate tropomyosin genes described to date is the rat a-TM gene, as presented in this study ( Fig.…”

“…It is notable that the polyadenylation signal attaaa does not conform to the conventional aataaa signal. However, the attaaa sequence is found near the 3' end of a human skeletal tropomyosin cDNA, skaTM.2 (40). The second polyadenylation signal used is 1,865 nt downstream of the exon 9c coding sequence, corresponds to the polyadenylation site for exon 9d, and is used in the cDNA clone pOklO (Fig.…”

“…The tropomyosins of chickens (2,24,36,39,56), D. inelatiogaster (22,30), humans (9,(40)(41)(42), quails (21,53), and rats (23,54,64,66) are all encoded by multigene families. Further diversity results from the presence of alternative transcriptional promoters (2,9,22) and alternative splicing of the primary gene transcripts (2, 9, 21-23, 30, 36, 40, 41, 54).…”

“…Tropomyosins are a diverse group of proteins with distinct isoforms present in striated muscle, smooth muscle, and nonmuscle cells (2,9,23,36,40,55,56). They are elongated structural proteins that have a simple dimeric structure consisting almost entirely of an alpha-helical coiled-coil (reviewed in reference 58).…”