PROMOTER STRUCTURE OF THE RNA-POLYMERASE-II LARGE SUBUNIT GENE IN CAENORHABDITIS-ELEGANS AND C-BRIGGSAE

The 5'-end of the Caenorhabditis elegans ama-1 gene transcript, which encodes the largest subunit of RNA polymerase II, was cloned. Sequenci ng revealed that the message is trans-spliced. To characterize the Ce- ama-1 promoter, DNA sequence spanning 3 kb upstream from the initiatio n codon was determined. Typical elements, such as TATA and Sp1 sites, were absent. The homologue of ama-1 in C. briggsae, Cb-ama-1, was isol ated and its 5' flanking sequence compared with that of Ce-ama-1, reve aling only limited similarity, although both sequences included a pote ntial initiator-class transcriptional regulator and phased repeats of an AT(3)C motif. The latter elements are postulated to facilitate DNA bending and may play a role in transcription regulation.