Project description:Malaria is as one of the most debilitating mosquito-borne global health burdens. While much of the malaria and mosquito-borne disease attention have focused on Africa, South East Asia accounts for a sizable portion of the malaria global burden. Moreover, about 50% of the Asian malaria incidence and deaths have been from India. The completion of genome sequence of Anopheles stephensi, a major malaria vector in Asia, offers new opportunities for global health innovation, not to mention for progress in deciphering the vectorial ability of this mosquito species at a molecular level. Moving forward, tissue-based expression profiling would be the next obvious step in understanding gene functions of Anopheles stephensi. We report here the first study, to the best of our knowledge, on transcriptomic profile of four important organs of an adult female Anopheles stephensi mosquito (midgut, Malpighian tubules, fat body and ovary). In all, we identified over 21,000 transcripts corresponding to more than 12,000 gene loci from these four tissues. This study provides the tissue-based expression profiles of majority of annotated transcripts in Anopheles stephensi genome, and the dynamics of alternative splicing in these tissues. Understanding the transcript expression and gene function at the tissue level would immensely help in enhancing our knowledge of this important vector and decipher the putative role of these tissues. This knowledge might in turn provide the basis of selection of candidates for future studies on vectorial ability and novel molecular targets to intercept malaria transmission.
Project description:A piggyBac transposon-based gene trap element was transformed into the Asian malaria vector, Anopheles stephensi, and remobilized using the jumpstarter approach using genetic crosses. Individuals that displayed a gene trap remobilization event were then photodocumented and their RNA and DNA complements were extracted. The DNA compelement was used to determine the genomic insertion site, while the RNA was used to determine the transcript coverage of the genes into which the transposons inserted. In nearly half of the cases, insertion was identified to fall within introns present in the 5'-UTR of transcripts- which are not indicated in the current ab initio models for Anopheles stephensi. The ability to utilize next generation RNA-Seq elucidated the functionality of the gene trap elements that inserted outside of the ab initio gene models, providing clear evidence that not only was the gene trap element working properly, but that it also had a bias towards 5'-end insertion, in particular, 5'-UTR intronic insertion.
