Isolation and characterization of As60A, a transforming growth factor-beta gene, from the malaria vector Anopheles...

We have isolated the first mosquito member of the TGF-beta superfamily, As60A. As60A is a single copy gene, approximately 5 kb in length and encodes eight exons. Here we report the isolation and characterization of two of four transcripts produced from this gene. The transcripts As60A(1)and As60A(2)encode related 5'UTR/exon 1 sequences. As60A is most similar to the 60A genes from Drosophila and is thus a member of the Dpp/BMP subfamily of the TGF-beta superfamily. The splice junction of intron 2 is conserved among As60A, BMP2, BMP4, Tc-Dpp, Bm-tgh-1, TGF-beta1 and Dpp. Intron 2 also contains three putative binding sites for a Dorsal/Gambif1 transcription factor. The large number of introns and the conservation of intron 2 indicate that As60A is relatively ancient compared to the other arthropod TGF-beta genes. We also propose that As60A plays a role in the mosquito immune response to Plasmodium infection.