Isolation and characterization of As60A, a transforming growth factor-betagene, from the malaria vector Anopheles stephensi

We have isolated the first mosquito member of the TGF-beta superfamily, As6 0A, As60A is a single copy gene, similar to 5kb in length and encodes eight exons. Here we report the isolation and characterization of two of four tr anscripts produced from this gene. The transcripts As60A(1) and As60A(2) en code 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-b eta 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 thr ee putative binding sites for a DorsaUGambif1 transcription factor. The lar ge number of introns and the conservation of intron 2 indicate that As60A i s relatively ancient compared to the other arthropod TGF-beta genes. We als o propose that As60A plays a role in the mosquito immune response to Plasmo dium infection. (C) 2001 Academic Press.