Cloning and characterization of TIMP-2b gene in grass carp

Tissue inhibitors of metalloproteinases (TIMPs) are the primary inhibitors of matrix metalloproteinases (MMPs) in tissues. In this study, a TIMP-2 gene was isolated from grass carp Ctenopharyngodon idella (CiTIMP-2b) and characterized. This cDNA sequence encoded a signal peptide, N- and C-terminal domains. CiTIMP-2b is highly homologous to the orthologous in zebrafish and other teleosts, suggesting TIMP-2b is highly conserved during teleost evolution. CiTIMP-2b gene is expressed in a wide range of tissues including blood, brain, muscle, trunk kidney, liver, head kidney, skin, spleen, heart, gill, intestine and fin, with the highest level of transcripts in spleen. Upon challenge with Aeromonas hydrophila, its expression was significantly up-regulated in all tissues. The CiTIMP-2b transcript is present at unfertilized eggs, which suggests that CiTIMP-2b transcript is maternally inherited. These results suggest that the CiTIMP-2b would play an important role in the A. hydrophila-related diseases and early embryonic development stages in grass carp.