The Drosophila ras2 and rop gene pair are governed by a common promoter. Characterisation of the Drosophila ras2/rop bidirectional promoter has revealed that a single major protein complex (M), composed of two subunits (factors A and B) interacts with two central promoter domains (regions A and B). To define the transcriptional control elements contained within region A (-58 to -39) we performed mutational analysis on several putative elements. This approach has revealed that the conserved TATA-like, SRE-like and GATA-like sequences do not interact with factor A and are not regulatory elements of this promoter. Nucleotides -56 to -49 bear perfect homology to the Drosophila DNA replication-related element (DRE, TATCGATA) found in two genes involved in DNA replication and cell proliferation, the Drosophila proliferating cell nuclear antigen (PCNA) and DNA polymerase a. A CG pair (-53 and -52) has been pinpointed as cardinal for factor A binding. Factor A has been partially purified and identified as a 20 kDa polypeptide by photo-chemical crosslinking analysis.

Related Articles