Molecular cloning of grass carp growth hormone receptor and its functional interaction with silver carp growth hormone.

A novel grass carp growth hormone receptor (gcGHR) cDNA was cloned by RT-PCR method. CHO-K1 cells were transfected with eukaryotic expression vector pcDNA3.0 containing gcGHR entire coding region, resulting in a stable CHO cell line expressing gcGHR (CHO-gcGHR). Bioactivity assay revealed that silver carp growth hormone (scGH) bound gcGHR with dissociation constant (Kd) value of 1.96 nM and stimulated CHO-gcGHR cells proliferation with the sensitivity of 20 ng/ml. The cells proliferation assay was also provided to measure fish growth hormone levels of pituitary and refolded protein.