Structural insights of Labeo catla (catla) myxovirus resistance protein,GTP binding recognition and constitutive expression induced with Poly I:C

Abstract

The Myxovirus resistance (Mx) proteins are critical effectors belonging to the super-family of guanidine triphosphatase, often stimulated by type I interferon (IFN) and mediates antiviral responses to restrict the replication of numerous viral genes in fishes. In teleosts, Mx proteins display diverse and complicated antiviral activity in different species. The present investigation seeks to characterize the Mx gene from Labeo catla upon induction by double-stranded (ds) RNA, polyinosinic-polycytidylic acid, (poly I: C). Molecular modeling and all-atoms molecular dynamics (MD) simulations were employed to understand the architecture of the GTPase domain and its plausible mode of GTP recognition in Mx protein. The full-length L. catla Mx (LcMx) gene sequence (1821 bp nucleotides) encodes an open reading frame of 606 amino acids. Domain search indicated conserved tripartite domain architecture of LcMx and forms a major cluster with the Mx from other teleosts. The positively charged Arginine and polar Glutamine residues from helix 3 and 4 of stalk region LcMx aid in homo-oligomerization. MD simulation portrayed the role of conserved critical residues aid in GTP recognition by the GTPase domain which perfectly corroborates with experimental findings and prior MD studies. After injection of poly I:C, the temporal mRNA profile showed that LcMx expression was significantly elevated in the spleen, brain, kidney, liver, muscle, heart, intestine, and gill tissues. Collectively, these results suggest that the elevated expression of the major innate immune defense gene Mx was able to inhibit the poly I: C mediated virulence in fish.

Communicated by Ramaswamy H. Sarma

Keywords:

• Myxovirus resistance proteins
• poly I: C
• molecular dynamics simulation
• interferon type I
• open reading frames
• guanosine triphosphate

Acknowledgments

The authors are thankful to the Department of Biotechnology, Govt. of India, New Delhi for financial support. We would extend sincere gratitude to the Director, ICAR-CIFA, Bhubaneswar, Odisha for constant support for providing essential facilities to conduct the experiment.

Authors’ contributions

BKD: Conceptualization, designed, and overall monitoring the experiment. SPP and PR: Performed the experiment. BKD, SPP, and BD: Analyzed the data. SPP, BKD, and BD: Original draft. BKD, DRS, AKR, and BKB: Writing, Review, and Editing.

Data availability statement

A partially amplified cDNA fragment of 1770 bp was submitted to the NCBI GenBank with the accession number: KP282448. The complete sequence of 1821 bp was obtained after cloning the unknown ends of the cDNA by RACE and sequencing a rapid amplification of the final cDNA end product, the same was submitted to NCBI GenBank with the accession number: MT251365.

Disclosure statement

The author declares that they have no competing interests.

Ethics statement

The experimental work was carried out with due approval of the animal ethical committee (Approval Number. CIFA/EC/2019/54) of ICAR-Central Institute of Freshwater Aquaculture (ICAR-CIFA), Kausalyaganga, Bhubaneswar, Odisha, India.

Additional information

Funding

The author(s) reported there is no funding associated with the work featured in this article.