Abstract
Heterocyst is a terminally differentiated cell of cyanobacteria which is specialized in nitrogen fixation. Upon limitation of combined nitrogen in the medium, heterocysts are formed with a semi-regular spacing of 10-15 cells. Heterocyst differentiation involves a complex series of coordinated cellular process to develop an efficient environment for nitrogen fixation. To understand how heterocyst differentiation is regulated, it is crucial to identify genes related to heterocyst differentiation. We analyzed a pattern of gene expression after nitrogen deprivation using oligo DNA microarray in Anabaena PCC 7120 and a hetR mutant strain, DR884a. The HetR protein is a key regulator in the regulation of heterocyst differentiation. Disruption of hetR blocks the earliest stage of heterocyst differentiation and overexpression of hetR leads to ectopic formation of heterocysts even under condition replete with combined nitrogen. We try to identify genes related to heterocyst differentiation by comparing gene expression patterns in these two strains.
