Nuclear factor recognition sites in the gut-specific enhancer region of anAnopheles gambiae trypsin gene

The major digestive enzyme of Anopheles gambiae is encoded by the trypsin 1 gene. This gene is expressed exclusively in the gut and its mRNA abundance increases after ingestion of a blood meal. Previous experiments with trans genic Drosophila have shown that the enhancer region, from nucleotide -360 bp to -150 bp upstream of the transcription initiation site, is necessary t o drive the gut-specific expression of a reporter gene (Skavdis et al., 199 6. EMBO J. 15, 344-350). In this study, we defined DNA sequences within thi s region that are capable of binding nuclear factors from either gut or non -gut tissues. By electrophoretic mobility shift assays, we determined that a gut-specific nuclear factor recognizes and binds to three sites in the en hancer region with a consensus sequence TYCAAGT. Another factor, found in m any tissues, recognizes and binds to at least two additional sites with a c onsensus sequence ACGATA. This study defines for the first time for an inse ct gut-specific enhancer, specific sequences that interact with nuclear fac tors. (C) 1998 Elsevier Science Ltd. All rights reserved.