Analysis of ovary-specific genes in relation to egg maturation and female nutritional condition in the mosquitoes Georgecraigius atropalpus and Aedes aegypti (Diptera: Culicidae)

• Published in: Journal of insect physiology 2013-03, Vol.59 (3), p.283-294
• Main Authors: Telang, Aparna, Rechel, Julie A., Brandt, Jessica R., Donnell, David M.
• Format: Article
• Language: English
• Subjects: adults; Aedes - genetics; Aedes - growth & development; Aedes - metabolism; Aedes aegypti; Aedes atropalpus; Anautogeny; animal ovaries; Animals; apolipophorin; Apolipophorin III; Autogeny; binding proteins; blood; blood meal; Culicidae; Culicidae - genetics; Culicidae - growth & development; Culicidae - metabolism; digestion; Diptera; ecdysteroids; eclosion; egg production; eggs; expressed sequence tags; Female; Gene Expression Regulation, Developmental; genes; Gonadotropin inducible transcription factor; homeostasis; Insect Proteins - genetics; Insect Proteins - metabolism; larvae; Molecular Sequence Data; nutritional status; Ochlerotatus; Ochlerotatus atropalpus; Oogenesis; ovarian development; Ovary - cytology; Ovary - growth & development; Ovary - metabolism; Ovum - growth & development; Ovum - metabolism; Oxysterol binding protein; Species Specificity; SSH; suppression subtractive hybridization
• ISSN: 0022-1910; 1879-1611
• DOI: 10.1016/j.jinsphys.2012.11.006

► Autogenous mosquito G. atropalpus offers a study of oogenesis sans bloodmeal. ► SSH of transcripts from autogenous ovaries identified ESTs relevant to oogenesis. ► RNAi studies in A. aegypti revealed potential functions of specific genes. ► Knockdown of APO transcripts lead to reduced lipid levels in tissues. ► Knockdown of OSBP transcripts suggests a role in ecdysteroid production. Analysis of the reproductive physiology of anautogenous mosquitoes at the molecular level is complicated by the simultaneity of ovarian maturation and the digestion of a blood meal. In contrast to anautogenous mosquitoes, autogenous female mosquitoes can acquire greater nutrient stores as larvae and exhibit higher ovarian production of ecdysteroids at adult eclosion. These features essentially replace the role of a blood meal in provisioning the first batch of eggs and initiating egg development. To gain insight into the process of ovary maturation we first performed a transcript analysis of the obligatory autogenous mosquito Georgecraigius atropalpus (formerly Ochlerotatus atropalpus). We identified ESTs using suppressive subtractive hybridization (SSH) of transcripts from ovaries at critical times during oogenesis in the absence of blood digestion. Preliminary expression studies of genes such as apolipophorin III (APO) and oxysterol binding protein (OSBP) suggested these genes might be cued to female nutritional status. We then applied our findings to the medically important anautogenous mosquito Aedes aegypti. RNAi-based analyses of these genes in Ae. aegypti revealed a reduction in APO transcripts leads to reduced lipid levels in carcass and ovaries and that OSBP may play a role in overall lipid and sterol homeostasis. In addition to expanding our understanding of mosquito ovarian development, the continued use of a comparative approach between autogenous and anautogenous species may provide novel intervention points for the regulation of mosquito egg production.