Cloning and expression of Iranian Turkmen-thoroughbred horse follicle stimulating hormone in Pichia pastoris

Follicle stimulating hormone (FSH) plays an essential role in reproductive physiology and follicular development. A new variant of the equine fsh (efsh) gene was cloned, sequenced, and expressed in Pichia pastoris (P. pastoris) GS115 yeast expression system. The full-length cDNAs of the efshα and efshβ chains were amplified by reverse transcription polymerase chain reaction (RT-PCR) using the total RNA isolated from an Iranian Turkmen-thoroughbred horse's anterior pituitary gland. The amplified efsh chains were cloned into the pPIC9 vector and transferred into P. pastoris. The secretion of recombined eFSH using P. pastoris expression system was confirmed by Western blotting and immunoprecipitation (IP) methods. The DNA sequence of the efshβ chain accession number JX861871, predicted two putative differential nucleotide arrays, both of which are located in the 3′ UTR. Western blotting showed a molecular mass of 13 and 18 kDa for eFSHα and eFSHβ subunits, respectively. The expression of desired protein was confirmed by protein G immunoprecipitation kit. eFSH successfully expressed in P. pastoris. These findings lay a foundation to improve ovulation and embryo recovery rates as well as the efficiency of total embryo-transfer process in mares.