Bovine skeletal muscle cells predominantly express a vascular cell adhesion molecule-1 seven-Ig domain splice form

Abstract

Vascular cell adhesion molecule-1 (VCAM-1), which has several alternatively splicing variants, plays a role in myotube formation. To investigate which form functions in myogenesis, we analyzed VCAM-1 mRNA expression in bovine skeletal muscle cells. We detected the expression of two VCAM-1 splice forms in the muscle tissue and in the primary satellite cell culture. The longer form was predominantly expressed at the muscle and during myotube formation of the cells. The nucleotide sequences of the two forms were determined by cDNA direct sequencing. The sequence data showed that the predominant form in skeletal muscle was a full-length VCAM-1 (VCAM-7D) that consists of seven immunoglobulin-like (Ig) domains, and the minor form was a novel six-domain form that lacks the seventh Ig domain. Compared to this, bovine pulmonary artery endothelial cells also express a variant which lacks domain 7, but VCAM-7D was not detected by RT-PCR in the culture. No VCAM-1 expression was detected in bovine kidney epithelial cell, lymph node epithelial cell, or leukemic B-lymphocyte culture even under stimulation by tumor necrosis factor-α. These data suggest that the splicing of the VCAM-1 gene alternatively varies depending on the cell type where it is expressed, and that VCAM-7D plays a predominant role in myotube formation.