Antimicrobial 2 (Cuperus et al. 2013) and avian ?-defensin

Antimicrobial peptides are crucial elements of the host non-specific innate immune system which play a major role as natural antibiotics by providing first line defense against microbial incursion. (Hancock etal., 2006, Zasloff.,2002).

AMPs are generally short, cationic, amphipathic and structurally diverse molecules that are widely present in nearly all life form 1. These molecules display extensive and strong antimicrobial activity against microbial assault primarily by destroying membrane integrity of the invading pathogens. Apart from being antimicrobial, AMPs perform immunomodulatory roles also by recruiting and activating innate and adaptive immune cells; hence they were named as host defense peptides. Majority of the AMPs are encoded by distinct genes, and a large number of structurally different HDPsnormally exist in a single species.

 Different groups of AMPs reported in birds include NK-lysin (Cuperus et al. 2013; Ishige et al. 2014), cathelicidin (Cuperus et al. 2013), liver-expressed antimicrobial peptide 2 (Cuperus et al. 2013) and avian ?-defensin (Cuperus et al. 2013; Ishige et al. 2015a) which endow them with tremendous innate immunity.

Liver-expressed antimicrobial peptide 2 (LEAP-2) is the second blood-derived peptide isolated firstly from human blood and displays antimicrobial activity and predominant expression in the liver. (Krause et al., 2003). This peptide belongs to cystein rich family of AMPs characterized by the presence of a four cystein conserved motif and twointracellular disulphide bridges. LEAP2 has been characterized from few organisms like human, monkey, pig, mouse, cow, and chicken 8-12. In chicken, Cleap2 gene consists of three exons and two introns, has been reported to be localized in chromosome 13 of chicken genome. Like other cationic HDP, LEAP2 also possess a signal peptide, a prepropeptide and an active mature peptide.

Cleap2 gene encodes a 76 amino acid  prepropeptide which is enzymatically processed by furin family of propeptide convertase to release mature peptide of 40 amino acid. The RXXR motif at cleavage site between prodomain and mature region of LEAP2 is conserved throughout vertebrates. Studies suggest that Human and channel catfish LEAP2 gene express several splicing variants as a result of alternative splicing. It is possible that LEAP2 gene employ splicing as a major mechanism of its regulation. In the present study, we compared the nucleotide and protein sequences of avian LEAP2   undefined undefined undefined undefined undefined undefined undefined undefined undefined undefinedundefined undefinedThe length of the text: 2488 (No spaces: 2153)