Involvement of the DNA replication-related element (DRE) and DRE-binding factor (DREF) in transcriptional regulation of the Bombyx mori PCNA gene.

The promoter region of the Bombyx mori gene encoding the proliferating cell nuclear antigen (PCNA), and its activating factor(s) were analyzed to ascertain similarities with Drosophila regulatory elements. Full promoter activity was established to reside within the region from -466 to +347 base pairs with respect to the transcription initiation site. Within this region, we found a sequence similar to the DNA replication-related element (DRE), 5'-TATCGATA, which is a promoter-activating sequence common to promoters of the Drosophila genes for DNA replication-related factors, including PCNA. A mutation in the DRE-like sequence of the B. mori PCNA gene promoter caused reduction of the promoter activity and also binding to the recombinant Drosophila DRE-binding factor (DREF). Furthermore, a factor(s) binding to the DRE sequence was detected in extracts of B. mori BmN4 cells. Monoclonal antibodies against Drosophila DREF inhibited the binding activity of the factor, as shown by gel mobility shift assays, and allowed specific detection of a 100 kDa protein on immuno Western blot analysis. These results suggest that the B. mori DREF homolog binds to DRE to regulate transcription of the PCNA gene.