Molecular characterization of Bax inhibitor gene TMBIM in response to heat stress in goats of semi arid region

Abstract

Bax inhibitor-1 (BI-1) gene, known as TMB1M6, is evolutionary conserved and regulates cell newlinesurvival in response to various stress in animals and plants. The Bax and Bcl-2 is the most important newlinegenes that regulate program cell death (PCD) and Caspase helps to degradation of cells. The present newlinestudy was carried out to analysed the TMB1M6 (Transmembrane Bax inhibitor motif) gene in relation to newlinestress susceptible and stress tolerant phenotypes in different goat breeds. The environmental temperature newlinewas varied from 45-49.40°C, relative humidity 14.33-27%, and THI 85.40-89.80. Phenotype of newlineindividuals were carried out basing on heart rate (HR) and respiration rate (RR) during peak heat stress newlineperiod and recognized as heat stress tolerance (HST) and heat stress susceptible (HSS). TMB1M6 newlinegenotyping was carried out by HRM (high resolution melting). The four different genotypes was blue newline(AA) 44.44%, red (AC) 36.11%, green (CC) 11.11%, purple (TT) 8.33%, analysed in sample. Frequency newlineof allele A, C and T was 0.56, 0.20 and 0.20. Transition 33.33 % and transversions 66.65% was observed. newlineTwo novel mutant were identified at base position 55(TgtC) in heat stress-tolerant (HST) individual in newlineBarbari goat. Similarly the mutation at base position 96(AgtC) was observed in heat stress-susceptible newline(HSS) individual in Jakhrana goat. The nucleotide sequence analysis indicated that the percent similarity newlineof TMBIM6 gene fragment of goat with cattle, human and mouse was 92.2, 85.2 and 80.9%, respectively. newlineFor expression analysis: of Bax, Bcl-2 and Caspase total RNA was isolated from blood and subjected to newlineRT-PCR. Relative fold expression of Bax at 3 month, 9 month, 12 month and adult was 0.9173, 22.19, newline0.3005, and 7.044 respectively in HST phenotype. Similarly, in HSS phenotype the relative fold newlineexpression of Bax gene at 3 month, 9 month, 12 month and adult was 0.061, 23.24, 0.552 and 22.97 newlinerespectively. The relative expression of Bax was significantly higher at 9 month age group compared to 3 newlinemonth, 12 month and adult in HST and HSS phenotypes. The ratio of relative expression of Bax was newlinesignificantly higher at 9 month compared to Bcl-2 and Caspase gene. Relative mRNA expression profile newlineof genes indicates that goat are more susceptible and tolerance during summer season. Higher expression newlineof Bax gene during summer indicated that susceptibility of cells to PCD. Based on this finding it can be newlineconcluded that heat stressed goats are more susceptible to cell apoptosis and also responsible for genetic newlinevariability. newline