Studies on expression of the c-ski gene in equine (thoroughbred) tissues

Abstract

A partial cDNA fragment of equine (Thoroughbred) c-ski gene (exon 1) was cloned by means of the polymerase chain reaction (PCR) amplification, and its nucleotide sequence was determined. The nucleotide and the deduced amino acid sequences of equine c-ski showed very high homology (>90°/o) with human and mouse c-ski, suggesting that this gene is highly conserved in different species of mammals. Genomic DNAs from other breeds of horse, e.g., Breton, New Zealand Pony, Shire, Anglo-Arab and Tokara Horse, were also subjected to PCR analysis. No difference, however, was observed in the nucleotide sequences of the partial c-ski DNA fragments examined. The patterns of c-ski gene expression in various male fetal equine tissues, i.e., cerebrum, lung, heart, skeletal muscles etc., obtained on day 180 of pregnancy, were analyzed by means of reverse transcriptase-mediated PCR (RT-PCR). In all the tissues examined, the expression of c-ski genes was confirmed. Northern blot analysis was carried out to assess the relative expression levels of c-ski genes in the male fetal equine tissues. In all tissues examined, two forms of the transcripts were detected at molecular sizes of 7.8 kb and 6 kb, respectively. In the cerebellum and the lung, the relative expression levels were high. The expression levels in skeletal muscles were moderate compared to the other tissues. The small population size of satellite cells may explain the relatively low expression levels of c-ski genes in the well developed skeletal muscles.