Analysis of two transcription activation elements in the promoter of the developmentally regulated con-10 gene of Neurospora crassa

The con-10 gene of Neurospora crassa is activated during conidiation, CRS-B (conidiation response sequence-B) and CGE (con-10 general enhancer) elemen ts have been proposed to function as sites of transcriptional activation an d as possible elements that confer developmental regulation to con-10, In a specific analysis of the roles of these elements we found that two CRS-B e lements are necessary for full activation of con-10 during macroconidiation , whereas two CGE elements are functionally redundant, such that a single C GE is sufficient for maximal expression, However; CRS-B and CGE elements ar e not sufficient for developmental activation of a reporter gene, The CRS-B element was further dissected and one of the CRS-B elements appears to fun ction in repression as well as activation, con-10 is also highly expressed during microconidiation, a different form of asexual sporulation, but we sh ow here that CRS-B elements do not play a significant role in con-10 expres sion during microconidiation, Both CRS-B elements contribute to basal con-1 0 expression during mycelial growth, con-10 is also regulated by light, and CRS-B and CGE elements may play minor roles in controlling con-10 expressi on in response to tight, (C) 1998 Academic Press.