Differential regulation of Janus kinase 3 (JAK3) in bovine preovulatory follicles and identification of JAK3 interacting proteins in granulosa cells

Janus kinase 3 (JAK3) is a member of the membrane-associated non-receptor tyrosine kinase protein family and is considered predominantly expressed in hematopoietic cells. We previously identified JAK3 as a differentially expressed gene in granulosa cells (GC) of bovine preovulatory follicles. The present study aimed to further investigate JAK3 regulation, to identify protein binding partners and better understand its mode of action in bovine reproductive cells. GC were obtained from small follicles (SF), dominant follicles at day 5 of the estrous cycle (DF), and ovulatory follicles, 24 h following hCG injection (OF). RT-PCR analyses showed greatest expression of JAK3 in GC of DF, while JAK3 expression was downregulated in OF (P