The Arabidopsis SERRATE Gene Encodes a Zinc-Finger Protein Required for Normal Shoot Development

Organogenesis in plants depends upon the proper regulation of many genes, but how such necessary changes in gene expression are coordinated is largely unknown. The serrate (se) mutant of Arabidopsis displays defects in the initiation and elaboration of cotyledons and post-embryonic lateral organs. Cloning the SE gene revealed that it encodes a protein with a single, ${\rm C}_{2}{\rm H}_{2}\text{-type}$, zinc finger related to genes in other eukaryotes. Consistent with a role in organogenesis, the SE gene is transcribed in shoot meristems and in emerging organ primordia throughout development. Expression of the SE cDNA under the control of a heterologous promoter caused both accelerated and arrested plant growth, and these phenotypes were due to overexpression and co-suppression of the SE gene, respectively. Our analysis of the se mutant and the SE gene suggests a role for the SE gene product in regulating changes in gene expression via chromatin modification. Consistent with this proposed function, a synergistic double mutant phenotype was seen for plants mutant at both the SE locus and the locus encoding the largest subunit of chromatin assembly factor I.