Abstract
The full length sequence of the beta FSH gene of tilapia (Oreochromis mossambicus) was determined. Its transcriptional unit spans 2.7 kb and contains two introns: the first (1256bp) is within the 5' untranslated region while the second (957 bp) is in the conserved position at the 38th amino acid of the mature peptide. RT-PCR studies revealed that beta FSH gene expression involves two mRNA transcripts produced by alternate splicing of the first intron, without altering the peptide sequence. Similar splicing patterns were found also in other tilapia species and hybrids indicating that this phenomenon is not species specific. A competitive RT-PCR (CRT-PCR) was developed to evaluate the ratio of the variants. Our current data indicate that although the total amount of beta FSH transcript was increased in response to GnRH (0.1 nM), the ratio of the two splice variants remained constant.