The Role of ASF1 and CAF-1 in Morphogenesis of Arabidopsis

Abstract

CAF-1, a histone binding complex, assembles nucleosome preferentially onto newly replicated DNA in SV40 DNA replication in vitro system. ASF1, another histone binding protein, is known to facilitate CAF-1-dependent nucleosome assembly in vitro. Many other observations suggested that CAF-1 and ASF1 play a critical role in nucleosome assembly during DNA replication also in proliferating cells. However, physiological implications of those factors in multicellular organisms remain to be unknown.
In order to analyze physiological role of ASF1, we isolated T-DNA inserted mutants of ASF1a and ASF1b, two functional homologues of ASF1 in Arabidopsis. Although asf1a and asf1b mutants did not show any significant morphological phenotypes so far now, asf1a;asf1b double mutants showed distinct phenotypes including decreased the number of lateral roots and defect in the cell files of RAM. Our observations implied that ASF1