Cloning and expression profiling polycomb gene VERNALIZATION INSENSITIVE 3 in tomato

VERNALIZATION INSENSITIVE 3 (VIN3) is a chromatin remodelling protein that is induced by low temperatures and is required for the vernalization response in Arabidopsis thaliana. VIN3 is one of the polycomb group (PcG) proteins, which mediates epigenetic repression of FLOWERING LOCUS C (FLC) in A. thaliana. Here, we present cloning, characterization, and expression of a putative SlVIN3 gene in tomato (Solanum lycopersicum L.) by isolating cDNA clones corresponding to SlVIN3 gene using primers designed based on conserved sequences between PcG genes in A. thaliana and tomato. The SlVIN3 cDNAs were cloned into a pBS plasmid and sequenced. Both 5′ and 3′ RACE were generated and sequenced. The flcDNA of 2 823 bp length for the SlVIN3 gene was composed of 5’UTR (336 bp), ORF (2 217 bp), and 3’UTR (270 bp). The translated ORF encoded a polypeptide of 739 amino acids. Alignment of deduced amino acids indicates that there are highly conserved regions between tomato SlVIN3 predicted protein and plant VIN3 gene family members. Both unrooted phylogenetic trees constructed using the maximum parsimony and maximum likelihood methods indicate that there is a close relationship between SlVIN3 predicted protein and VIN3 protein of Vitis vinifera. The expression of SlVIN3 gene remained high during floral organ differentiation and growth and decreased when the fruit started to develop.