Abstract
MALE STERILITY1 (MS1) gene of Arabidopsis encodes a nuclear protein with a PHD-finger motif, and is involved in microspore maturation after meiosis. Here we examined the MS1 function. We introduced a chimeric fusion construct of MS1 and a transcriptional repression domain (MS1-SRDX) into wild-type Arabidopsis, and the transgenic plants showed ms1-like semi-sterile phenotype. Since the repression domain has an ability to convert various kinds of DNA-binding transcriptional activators to dominant repressors, this suggested that MS1 functioned as a transcription factor. The PHD motif was required for the MS1 function. Phenotypic analysis of the ms1 mutant and the MS1-SRDX transgenic Arabidopsis indicated that MS1 was involved in pollen exine, pollen cytosol and tapetum development. Next, we searched for downstream genes regulated by MS1 by using dexamethasone-induction system. From these results, we discuss a roll of MS1 in microspore maturation. We also discuss existence of MS1 orthologs in higher plants.
