Asm-1 +, a Neurospora crassa Gene Related to Transcriptional Regulators of Fungal Development

This report describes the identification, cloning, and molecular analysis of Asm-1  + (Ascospore maturation 1), the Neurospora crassa homologue of the Aspergillus nidulans stuA (stunted A) gene. The Asm-1  + gene is constitutively transcribed and encodes an abundant, nucleus-localized 68.5-kD protein. The protein product of Asm-1  + (ASM-1), contains a potential DNA-binding motif present in related proteins from A. nidulans (StuA), Candida albicans (EFGTF-I), and Saccharomyces cerevisiae (Phd1 and Sok2). This motif is related to the DNA binding motif of the Swi4/Mbpl/Res family of transcription factors that control the cell cycle. Deletion of Asm-1  + destroys the ability to make protoperithecia (female organs), but does not affect male-specific functions. We propose that the APSES domain (ASM-1, Phdl, StuA, EFGTF-1, and Sok2) defines a group of proteins that constitute a family of related transcription factors involved in the control of fungal development.