Identification of single nucleotide variations in the Toll-like receptor 9 (TLR9) gene and its association to mastitis susceptibility in dairy cattle

ABSTRACT

Toll-like receptors (TLRs) play a significant role in the host immune response. The TLR9 recognizes CpG DNA of bacteria and stimulate both the innate and adaptive immune responses. In the present study, functional domain (LRR) of TLR9 gene of mastitis-affected cows in comparison to apparently healthy animals was analyzed for any nucleotide variation as it may influence host susceptibility to disease conditions. LRR domain of TLR9 was amplified and analyzed for single-strand conformational polymorphism (SSCP). Samples shown altered SSCP mobility pattern were sequenced. Three nucleotide variations each in the two regions of functional domain were identified and the one corresponding to G→C variation at position 2318 of reference sequence (Accession No. AJ509824), suggesting the possible association with mastitis. Though the nucleotide variation did not result in amino acid change, it created an additional restriction site for Hae III which can be utilized in developing a new polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) marker.

KEYWORDS:

• Cattle
• mastitis
• single nucleotide variation
• Toll-like receptor 9 (TLR9)

Acknowledgments

We sincerely thank the Ex-Dean and the present Dean, Rajiv Gandhi Institute of Veterinary Education and Research (RIVER), Puducherry, for providing the research facilities. We would also extend our sincere thanks and gratitude to all the faculty of Teaching Veterinary Clinical Complex, RIVER and Veterinary Dispensaries, Puducherry, for helping in sample collection.

Disclosure statement

No potential conflict of interest was reported by the authors.