Analyses of Temporal Regulatory Mechanism of the Chloroplast Division

Abstract

Chloroplasts are believed to have evolved from an cyanobacterial endosymbiont. In order to establish the permanent endosymbiotic relationship, the host cell has been regulated proliferation of the endosymbionts (chloroplasts) during proliferation of the host cell. Although several components of the chloroplast division apparatus, such as FtsZ and dynamin, have been identified and characterized, the regulatory mechanism of the chloroplast division is still poorly understood.
In unicellular monoplastidic red alga Cyanidioschyzon, the chloroplast division is linked to the cell division cycle of the host cell. By contrast, chloroplasts apparently divide nonsynchronously even in the same cell in higher plants, raising a question of how the timing of the chloroplast division is regulated in cells with multiple chloroplasts.
By investigating several Arabidopsis mutants, we found a novel regulatory mechanism of chloroplast division. We will discuss how the timing of chloroplast division is regulated in cell of higher plants.