Analysis of Gene Expression of Mesorhizobium loti by Genomic Macro-array

Abstract

Approximately 3800 clones which cover the whole genome of Mesorhizobium loti MAFF303099 were selected and spotted onto nylon filters to make genomic macro-array. Total RNAs were isolated from cultured cells in TY medium, in minimal medium and in carbon-starved medium, and from bacteroids (isolated from nodules, BD), then ³³P labeled cDNAs were prepared to uses as targets. Hybridizations were carried out and autoradiographs were analyzed by Array Vision. The overlap images of relative expression level of all the clones with the genome map were constructed for the each bacterial condition. These maps made it possible to understand the dynamics of gene expression on the life cycle of M. loti. There were several genes of which expression changed drastically depending on the condition. The expression levels of these genes were reconfirmed by real time RT-PCR. The functions of these genes are now investigating by molecular genetic techniques like gene disruption