Abstract：Abstract:Suppression subtractive hybridization method was employed to construct a cDNA library expressed in mammary gland of early and peak lactation stages of the Xinong Saanen goat. Osteopontin was one of the positive clones . The CDs of goat osteopontin gene was cloned from the goat mammary gland by RT-PCR , real-time reverse transcriptase-polymerase chain reaction (RT-PCR) was used to analysis the change of OPN mRNA level between early and peak lactation stages,The sequence was predicted and registered in GenBank EU295699. Osteopontin gene with an ORF of 834 nucleotides encoded a polypeptide of 277 amino acids with a putative signal peptide of 16 amino acids. The nucleotide sequence homology of osteopontin of Xinong Saanen goat was found to be 98%, 95% ,71% and 70% compared with that of sheep(AF_152416), bovine (NM_174187), human(DQ_846871) and mouse (NM_009263), while the amino acid sequence homology to be 98%, 91%,55% and 54%, respectively.The mRNA level of OPN gene in mammary gland of early lactation stages was 5.03 folds higher than that in peak stage normalized by housekeeping gene β-actin .Goat osteopontin had two additional potential binding motif s compared to humans’ and mouses’.
