Sequence Characterization of Forebrain Embryonic Zinc Finger-like (FEZL) Gene in Indian Zebu (Bos indicus) Cattle and their Crossbreds

Background: Forebrain embryonic zinc finger-like (FEZL) gene is an important candidate associated with mastitis resistance in dairy cattle. FEZL is involved in transcriptional regulation of neuronal development and there exists a crosstalk between neuronal development and immunity via downstream cytokine expression. A single glycine insertion into glycine stretch of FEZL gene has large effect on downstream cytokine pathway making the cows susceptible to mastitis. The present study was aimed to sequence characterize FEZL gene in Sahiwal (Bos indicus) and Karan Fries (Bos inidcus X Bos taurus) cattle. Methods: Sequence characterization of bovine FEZL gene was carried out by primer walking method. Ten sets of oligonucleotide primers were designed to synthesize overlapping fragments and generate the complete sequence of about 3.7 kb covering all exons and 5’ upstream regulatory and flanking regions. Result: A total of eight nucleotide variations including three INDELS and five substitution mutations were observed among FEZL gene sequences of Bos taurus, Bos indicus (Sahiwal) and Bos taurus X Bos indicus (Karan Fries) cattle. The conceptualized amino acid sequence of bovine FEZL gene in Sahiwal and Karan Fries cattle was found to have 13 tandem Glycine residues and a serine to proline change within exon 1 region. The percent identity of FEZL gene of Sahiwal and Karan Fries cattle was 99% with that of Bos taurus, 95% with dog, horse and pig, 94% with human, 93% with rabbit, 92% with marmoset, 89% with rat and 79% with chicken. Sequence characterization of ~0.7 kb 5’ flanking region showed that it is highly conserved among bovines and resulted in prediction of six putative sites for binding of transcription factors (including Elk-1, Oct-1, HNF4, Lmo2 complex, GATA-3 and Nkx2-5). Elucidation of Bos indicus FEZL gene will further form the basis to identify candidate gene markers for association with mastitis resistance/susceptibility in cattle.