Lightfoot, K., Department of Zoology, University of the Witwatersrand, Private Bag 3, WITS, 2050 Johannesburg, South Africa
Tai, A., Department of Zoology, University of the Witwatersrand, Private Bag 3, WITS, 2050 Johannesburg, South Africa
Segev, O., Department of Zoology, University of the Witwatersrand, Private Bag 3, WITS, 2050 Johannesburg, South Africa

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.