Abstract：Abstract CD320 (cluster of differentiation 320) is the cobalamin transporter receptor, which belongs to the low-density lipoprotein receptor family. CD320 plays an important role in cobalamin transfer process and regulates many physiological processes in mammalian. This study was undertaken to obtain the sequence of goat CD320 gene and its expression patterns in different tissues and development stages in goat testicle. The cDNA of CD320 gene was cloned by RT-PCR, and was further bioinformatics analyzed. The qRT-PCR technology was utilized to detect the expression patterns of CD320 in different tissues (heart, liver, spleen, lung, kidney, skeletal muscle, ovary, testicle) in adult and expression profiles of various developmental stages. The results showed that the goat CD320 gene sequence was first obtained (GenBank No.:MG560828). The full-length cDNA sequence was 877 bp and the ORF was 768 bp; encoding a protein of 255 aa. The protein weight was 27.18 kD, had 2 LDLRA (low-density lipoprotein receptor type A) domains (residues 53~89 and residues 129~171) and a transmembrane region (residues 20~224). The results of the homologous sequence alignment showed that the protein of goat and other species in the core site of the LDLRA domain and the transmembrane region was highly conserved. The phylogenetic analysis showed that goat together with ruminants such as sheep (Ovis aries) and cattle (Bos taurus), belonged to the Bovidae of Ruminantia. The transcriptional expression displayed that CD320 expressed in all tissues (heart, liver, spleen, lung, kidney, skeletal muscle, ovary, testicle) and the expression of lung, testicle and muscle was significantly higher than other tissues (P<0.01). In the testicle, the expression of CD320 was lower in fetus and 2-months-old (suckling period), and increased rapidly in 6-month-old (sexual maturity), which was significantly higher than that in fetus and suckling period (P< 0.01), and then decreased. In the epididymis, overall, the expression of CD320 in the epididymis of fetal stage was lowest. The expression of sexual maturation was the highest in caput epididymidis and cauda epididymidis, and the difference was significant compared with other stages (P<0.01), and the expression decreased after body maturation. But the expression of suckling period was the highest in the corpora epididymidis, and there was a significant difference compared with other periods (P<0.01). These results suggested that CD320 may participate in the physiological process development of testicles, epididymis and spermatogonial differentiation in goat. This study provides the basic for further study on CD320 gene function in goat.
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