Molecular cloning, sequence identification and tissue expression profile of three novel sheep (Ovis aries) genes - BCKDHA, NAGA and HEXA

ABSTRACT

The complete coding sequences of three sheep genes- BCKDHA, NAGA and HEXA were amplified using the reverse transcriptase polymerase chain reaction (RT-PCR), based on the conserved sequence information of the mouse or other mammals. The nucleotide sequences of these three genes revealed that the sheep BCKDHA gene encodes a protein of 313 amino acids which has high homology with the BCKDHA gene that encodes a protein of 447 amino acids that has high homology with the Branched chain keto acid dehydrogenase El, alpha polypeptide (BCKDHA) of five species chimpanzee (93 percent), human (96 percent), crab-eating macaque (93 percent), bovine (98 percent) and mouse (91 percent). The sheep NAGA gene encodes a protein of 411 amino acids that has high homology with the alpha-N-acetylgalactosaminidase (NAGA) of five species human (85 percent), bovine (94 percent), mouse (91 percent), rat (83 percent) and chicken (74 percent). The sheep HEXA gene encodes a protein of 529 amino acids that has high homology with the hexosaminidase A(HEXA) of five species bovine (98 percent), human (84 percent), Bornean orangután (84 percent), rat (80 percent) and mouse (81 percent). Finally these three novel sheep genes were assigned to GenelDs 100145857, 100145858 and 100145856. The phylogenetic tree analysis revealed that the sheep BCKDHA, NAGA, and HEXA all have closer genetic relationships to the BCKDHA, NAGA, and HEXA of bovine. Tissue expression profile analysis was also carried out and results revealed that sheep BCKDHA, NAGA and HEXA genes were differentially expressed in tissues including muscle, heart, liver, fat, kidney, lung, small and large intestine. Our experiment is the first to establish the primary foundation for further research on these three sheep genes.