In-silico search of virus-specific host microRNAs regulating avian influenza virus NS1 expression.

Avian influenza is a highly contagious viral infection caused by avian influenza virus type A of the family Orthomyxoviridae primarily affecting the avian species. The non-structural protein 1 (NS1) encoded by the NS1 gene of the virus is critical in establishing the infection. NS1 protein acts to suppress the virus-induced host interferon response and also inhibit Protein kinase R activation thereby helping the virus to establish the infection. MicroRNAs (miRNA) are small regulatory endogenous non-coding RNAs of ~22 nucleotides in length located within introns of coding and non-coding genes, exons of non-coding genes or inter-genic regions. miRNAs can target the gene at various sites and effectively reduce or shut down its expression. In this study, set of differentially expressed chicken miRNA identified by deep sequencing H5N1 infected and SPF chicken lung were computationally analyzed, to identify targets in the NS1 gene. 300 differentially expressed miRNAs were then analyzed individually for target sites in gi|147667147|gb|EF362422.1| influenza A virus (A/chicken/India/NIV33487/06(H5N1)) segment 8, complete sequence using RNAhybrid 2.2. The analysis yielded gga-miR-1658* as the potential miRNA which is targeting the NS1 gene of H5N1 genome.