| MicroRNAs (miRNAs) are a category of endogenous and petite RNA molecules known to be involved in a wide range of biological processes including cell differentiation, signal transduction, carcinogenesis and cell death. They range from 19-23 nucleotides in size and regulate gene expression by targeting the 3' untranslated region (UTR) of the messenger RNAs (mRNAs). miRNAs negatively regulate expression of protein coding genes in several species such as plants, humans, animals and viruses. miRNAs bind with perfect complementarity in plants and imperfect complementarity in animals, humans and other species to repress gene expression. In general, each miRNA is known to regulate more than 100 target genes. Currently miRNAs and their mRNA targets can be identified computationally. miRNAs play a vital role in host - virus interaction during infections. The host miRNAs alter viral gene expression to shut them off, while virus encoding miRNAs suppress host immune system and help viruses evade innate host immune response. Infectious laryngotracheitis virus (ILTV) is an alphaherpesvirus from the herpesviridae family with a large genome of ∼150kb. ILTV triggers acute respiratory disease in chicken. In this thesis, seven miRNAs encoded by ILTV were identified and their expressions were determined. |
