A cytoskeletal actin gene in the mosquito Anopheles gambiae.

Five actin genes have been identified in the mosquito Anopheles gambiae, and a constitutively expressed actin gene has been chosen for detailed analysis. We have physically mapped and sequenced this gene and six associated cDNAs, including translated coding regions, as well as the 5' and 3' flanking sequences. Analysis of stage-specific RNA shows this gene to be present in all stages of mosquito development and in an established A. gambiae cell line, thus indicating a cytoskeletal actin. In the sequence of the translated coding region and in pattern of expression, this gene is very similar to the cytoskeletal actin genes of Drosophila melanogaster, and in sequence, equally similar to the Artemia cytoskeletal actin gene 403 (99.2% identity among the three amino acid sequences). Sequencing of this A. gambiae actin gene (designated act1D for its location in chromosome division 1D) and selected cDNAs shows that it possesses three alternative leader sequences; thus the gene appears to have three alternative promoters. These promoters should ultimately prove useful in the production of transgenic constructs for constitutive expression.