The annexin gene family in the malaria mosquito Anopheles gambiae.

Annexins belong to a class of proteins that are known to bind to, and hold together structures such as membranes. Interestingly, Anopheles gambiae (and Drosophila melanogaster) annexins bind Plasmodium ookinetes in vitro. In the malaria mosquito three genes in two cytogenetic loci on chromosome arm 2R encode annexin homologues; their expression, monitored by quantitative real-time PCR during mosquito development, as well as in various tissues, revealed little fluctuation in patterns of expression during all life stages. A different mode of transcription was observed for the three genes in the midgut in relation to the uptake of a blood meal. Immunohistochemical staining of midguts and ovaries with polyclonal anti-annexin sera reveals that the Anopheles polypeptides are present in the epithelial cells of both tissues and associated with the plasma membrane.