The Arabidopsis MALE STERILITY1 (MS1) gene is a transcriptional regulator of male gametogenesis, with homology to the PHD-finger family of transcription factors

We report here the molecular characterisation of the Arabidopsis MALE STERI LITY1 gene, which is a critical sporophytic controlling factor for anther a nd pollen development. Homozygous ms1 mutants do not produce viable pollen, but are otherwise phenotypically normal. Degeneration of pollen occurs soo n after microspore release from the tetrads, at which time the tapetum also appears abnormally vacuolated. The MS1 gene is expressed at low levels in anthers from closed buds, with expression in the tapetum at the stage of mi crospore release. No expression is seen in open flowers. The deduced MS1 pr otein sequence shows strong homology to the PHD-finger motif found in known transcription factors from humans, yeast and higher plants. Six alleles of ms1 have been identified; all result in premature termination of the MS1 p rotein and loss of the PHD-finger motif. MS1 is likely to play a key role i n regulating transcription during specific stages of male gametogenesis and anther development. As such, MS1 provides a valuable tool for the manipula tion of male sterility in higher plants.