The Xenopus laevis TM-4 gene encodes non-muscle and cardiac tropomyosin isoforms through alternative splicing.
A full-length cDNA clone coding for a 248-amino-acid tropomyosin (TM) was isolated from a Xenopus laevis (Xl) oocyte cDNA library. This TM is very similar to the members of the non-muscle (nm) TM family that includes rat TM-4, human TM30pl and chicken cardiac fibroblast FT-C. An RNase protection assay showed that the corresponding transcript is expressed ubiquitously and revealed the presence of an alternative transcript in adult heart RNA. A full-length cDNA clone was isolated from an adult heart cDNA library using a nm TM-encoding cDNA probe. It encodes a muscle TM homologous to chicken FT-C and the corresponding mRNA is expressed in adult RNA and to a very low level in adult skeletal muscle. The two cDNAs correspond to two alternatively spliced isoforms of TM generated from the Xl TM-4 gene. These data, together with published observations, demonstrated that, in this amphibian, the cardiac muscle TM are synthesized from the TM alpha and TM-4 genes.
Hardy
S
S
Département de Biologie et Génétique du Développement, URA 256 CNRS, Université de Rennes I, France.
Thézé
N
N
Lepetit
D
D
Allo
M R
MR
Thiebaud
P
P
D017398:Alternative Splicing; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D018076:DNA, Complementary / Q000235:genetics; D015723:Gene Library; D008969:Molecular Sequence Data; D009132:Muscles / Q000737:chemistry; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D014018:Tissue Distribution; D014158:Transcription, Genetic; D014335:Tropomyosin / Q000235:genetics*; D029867:Xenopus Proteins; D014982:Xenopus laevis / Q000235:genetics*
D018076:DNA, Complementary; C501212:TPM4 protein, Xenopus; C501213:TPM4 protein, human; C501214:Tpm4 protein, rat; D014335:Tropomyosin; D029867:Xenopus Proteins