Molecular and expression characterization of growth hormone/prolactin family genes in the Prenant's schizothoracin

Abstract

The growth hormone/prolactin family genes are major participants in control of several complex physiologic processes, including growth, reproduction, and metabolism. In this study, total RNA was isolated from the pituitary of the Prenant's schizothoracin (Schizothorax prenanti), and SMART cDNA was synthesized from 100 ng total RNA. The full-length cDNAs of three GH/PRL family genes have been cloned and sequenced from the SMART cDNA library. The growth hormone of S. prenanti (SpGH) cDNA contains 1238 base pairs (bp) and encodes 215 amino acid (aa) residues; the prolactin (SpPRL) cDNA contains 1124 bp and encodes 209 aa residues; the cDNA sequence of somatolactin (SpSL) is 1290 bp in length, and encodes for a peptide of 234 aa residues. Although there is only about 22% aa sequence identity between the three deduced proteins, SpGH, SpPRL and SpSL, overall, the C-terminal region shows a higher identity. Multiple aa sequence alignments indicated the deduced SpGH, SpPRL and SpSL show high identities to that of goldfish and zebrafish, respectively. RT-PCR analysis revealed that the three hormones displayed different tissue distribution patterns. SpPRL transcripts were detected only in the pituitary of the Prenant's schizothoracin. SpSL was more widely distributed than SpPRL, high mRNA levels of SpSL were detected in the pituitary and low mRNA levels of SpSL were found in liver, kidney and heart. SpGH was expressed in nearly all tissues detected with the highest expression level in the pituitary.