Molecular Characterization of the 3'-Utrsequence of the Interferon-Gamma Gene and Its Expression Profile in the Ocular Conjunctiva of Amazon Buffaloes

Interferon-gamma is an important innate immunomodulatory inflammatory cytokine, whose molecular characterization can demonstrate how this gene may or may not be conserved in populations throughout the evolutionary process. Thus, the study aimed to characterize the 3'-UTR of the Interferon gamma gene and determine its expression profile in the ocular conjunctiva of Amazon buffaloes. For this, blood and ocular conjunctival tissue samples were collected from two hundred and five healthy slaughtered buffaloes in the State of Amapa, Brazil. For the conventional polymerase chain reaction, primers for the 3'UTR region of the Interferon-gamma gene were used and the products were purified, sequenced and edited by comparing the corresponding sequences from buffalo species and other domestic, wild and human mammals. They were aligned and compared using genetic similarity analysis and phylogenetic analysis, using Network 5.0 program and MrBayes, version 3.1.2, respectively. Conjunctival samples were submitted to mRNA quantification of the interferon-gamma to profile gene expression relative to the endogenous gene GAPDH and β-ACTIN. The study demonstrates high-level interferon-gamma genetic similarity between ruminants, with a network of haplotypes forming groups of ruminants, primates, carnivores, bats, cetaceans and isolated individuals such as suiformes and rhinos. Ruminants and cetaceans have a close phylogenetic relationship, while there were different evolutionary distances between buffalo and other mammalian species. The interferon-gamma gene was expressed in all animals in relation to endogenous genes. The results served to better understand the immune system of Amazonian buffaloes and to determine the evolutionary profile in relation to other mammalian species.