spacer gif spacer gif spacer gif spacer gif Online submission spacer gif
QUICK SEARCH:   [advanced]


spacer gif
     Home     Help     Feedback     Subscriptions     Archive     Search     Table of Contents    

First published online August 3, 2006
Journal of Experimental Biology 209, 3071-3078 (2006)
Published by The Company of Biologists 2006
doi: 10.1242/jeb.02349
This Article
Right arrow Figures Only
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Attardo, G. M.
Right arrow Articles by Raikhel, A. S.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Attardo, G. M.
Right arrow Articles by Raikhel, A. S.

Identification of two cationic amino acid transporters required for nutritional signaling during mosquito reproduction

Geoffrey M. Attardo*,{dagger}, Immo A. Hansen*, Shin-Hong Shiao and Alexander S. Raikhel§

Center for Disease-Vector Research, Department of Entomology and the Institute for Integrative Genome Biology, University of California Riverside, 3401 Watkins Drive, Riverside, CA-92521, USA

§ Author for correspondence (e-mail: alexander.raikhel{at}ucr.edu)

Accepted 26 May 2006

The defining characteristic of anautogenous mosquitoes is their requirement for a blood meal to initiate reproduction. The need for blood drives the association of vector and host, and is the primary reason why anautogenous mosquitoes are effective disease vectors. During mosquito vitellogenesis, a key process in reproduction, yolk protein precursor (YPP) gene expression is activated specifically in the fat body, the insect analogue of the vertebrate liver. We have demonstrated that blood meal derived amino acids (AAs) activate YPP genes via the target of rapamycin (TOR)-signal transduction pathway. Here we show, by stimulating fat bodies with balanced AA solutions lacking individual AAs, that specific cationic and branched AAs are essential for activation of the vitellogenin (vg) gene, the major YPP gene. Treatment of fat bodies with AA uptake inhibitors results in a strong inhibition of AA-induced vg gene expression proving that an active transport mechanism is necessary to transduce the AA signal. We identified two cationic AA transporters (CATs) in the fat body of Aedes aegypti females - Aa slimfast and iCAT2. RNAi knockdown of slimfast and iCAT2 results in a strong decrease in the response to AAs by the vg gene similar to that seen due to TOR inhibition. These data demonstrate that active uptake of specific AAs plays a key role in nutritional signaling during the onset of vitellogenic gene expression in mosquitoes and it is mediated by two cationic AA transporters.

Key words: TOR, vitellogenesis, slif, iCAT2, Aedes aegypti, fat body






© The Company of Biologists Ltd 2006