Expression of human serum albumin (HSA) mRNA in human granulosa cells: potential correlation of the 95 amino acid long carboxyl terminal of HSA to gonadotrophin surge-attenuating factor

Abstract

According to previous studies, gonadotrophin surge-attenuating factor (GnSAF), which is assumed to be produced in human granulosa cells, has a homology with the carboxyl terminal of the human serum albumin (HSA) protein. In an attempt to validate these findings, whole or partial expression of the HSA gene was studied by RT-PCR analysis in human granulosa cells from women undergoing IVF treatment. RT-PCR analysis of HSA RNA transcripts in luteinized granulosa cells was done in order to investigate the possible expression of the HSA gene. To ensure the specificity of PCR products, restriction enzyme and sequence analysis were performed. Western blot analysis was carried out to detect the possible expression of the albumin gene in granulosa cells. RT-PCR analysis and sequencing analysis of cDNA from granulosa cells revealed bands identical with those from the positive control for the amino as well as the carboxyl terminal corresponding to HSA gene at the cytoplasmic level. We have demonstrated that human granulosa cells express the carboxyl and amino terminal part of the HSA gene in levels comparable to those found in human hepatocytes. It is suggested that the coding gene for GnSAF may be a result of an alternative expression of HSA gene.