Identification Of Cis-Acting Control Sequences For The Developmentally Regulated brlA Gene In Aspergillus Nidulans

Abstract

An 11 Kbp SstI fragment has been identified which is capable of complementing a brlA⁻ deletion mutant when inserted at the trpC locus in Aspergillus nidulans. Deletions of the SstI fragment indicate that sequences as much as 4.5 Kbp upstream from the brlA coding region are necessary for proper developmental control of the gene. A fragment which removes 1.8 Kbp of sequence from the 5' end of the II Kbp SstI fragment partially complements a brlA⁻ deletion mutant when inserted at the trpC locus. Strains carrying this fragment differentiate conidiophores, but they are abnormally taller than wild type. Identification of a second transcript from the brlA region, brlAβ, has prompted me to design experiments which will distinguish the roles of the two transcripts and identify cis-acting control sequences which regulate the expression of each.