Isolation, sequence characterization, and tissue transcription profiles of two novel buffalo genes: INSIG1 and INSIG2.

Insulin-induced genes (INSIGs) are recently discovered genes that are involved in the metabolism of cholesterol and lipogenesis in animal tissues. In this study, two INSIG genes (INSIG1 and INSIG2) were isolated and characterized in 11 buffalo. The full-length coding sequence (CDS) of the buffalo INSIG1 consists of 831 bp which encodes a 276 amino acid protein with molecular mass 29.55 kD. And the INSIG2 CDS is 678 bp in length which encodes a 225 amino acid protein with molecular mass 24.87 kD. No polymorphisms were found in the CDSs of the buffalo INSIGs, but seven and two nucleotide differences were found in the CDSs between buffalo and other bovine species. Phylogenetic analyses based on the INSIG amino acid sequences showed that buffalo was grouped with other members in the Bovidae family. Four types of putative modification sites were detected in buffalo INSIG proteins. And two predicted microRNA target sites were found respectively in the CDSs of buffalo INSIG1 and INSIG2. The tissue expression analyses by quantitative PCR (qPCR) revealed that the buffalo INSIG1 was expressed in ten tissues tested. Among these tissues, the liver and mammary gland showed high expression levels. And the INSIG2 was only expressed in the brain, mammary glands, pituitary, abomasum, heart, and liver. Among these tissues, the mammary gland, brain, and pituitary demonstrated a high expression levels. These data provide the primary foundation for further insights into the buffalo INSIG genes.