Abstract
Although mosquito genome projects have uncovered orthologues of many known developmental regulatory genes, extremely little is known about mosquito development. In this study, the role of semaphorin-1a (sema1a) was investigated during vector mosquito embryonic ventral nerve cord development. Expression of sema1a and the plexin A (plexA) receptor are detected in the embryonic ventral nerve cords of Aedes aegypti (dengue vector) and Anopheles gambiae (malaria vector), suggesting that Sema1a signaling may regulate mosquito nervous system development. Analysis of sema1a function was investigated through siRNA-mediated knockdown in A. aegypti embryos. Knockdown of sema1a during A. aegypti development results in a number of nerve cord phenotypes, including thinning, breakage, and occasional fusion of the longitudinal connectives, thin or absent commissures, and general distortion of the nerve cord. Although analysis of Drosophila melanogaster sema1a loss-of-function mutants uncovered many similar phenotypes, aspects of the longitudinal phenotypes differed between D. melanogaster and A. aegypti. The results of this investigation suggest that Sema1a is required for development of the insect ventral nerve cord, but that the developmental roles of this guidance molecule have diverged in dipteran insects.
Highlights
Mosquito genome projects [1,2,3] have revealed orthologues of many genes that are known to regulate development of D. melanogaster, a well-characterized genetic model organism
Early axonogenesis in A. aegypti embryos is similar to that of D. melanogaster, our recent studies in this vector mosquito suggest that the function of Netrin signaling during embryonic ventral nerve cord development has evolved in insects [16]. siRNA-mediated knockdown of the A. aegypti frazzled (Aae fra) gene, which encodes a Netrin receptor, suggests that the developmental mechanisms responsible for regulating axon guidance in the embryonic nerve cord may have diverged among insects
A similar sema1a pattern of expression was previously reported in the developing central nervous system (CNS) of D. melanogaster [24]
Summary
Mosquito genome projects [1,2,3] have revealed orthologues of many genes that are known to regulate development of D. melanogaster, a well-characterized genetic model organism. Early axonogenesis in A. aegypti embryos is similar to that of D. melanogaster, our recent studies in this vector mosquito suggest that the function of Netrin signaling during embryonic ventral nerve cord development has evolved in insects [16].
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
