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

Abstract

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.

Knockdown of juvenile hormone acid methyl transferase severely affects the performance of Leptinotarsa decemlineata (Say) larvae and adults

“…RNAi efficiency varied dramatically among insect tissues . In Diptera, A. gambiae salivary glands and A. aegypti head and ovary showed a relatively lower response to RNAi than fat body, midgut and abdomen. In lepidopteran species, wing discs and epidermis were insensitive, followed by fat body, haemocytes, midgut and brain, whereas pheromone glands and silk glands were sensitive .…”

The Developmental Transcriptome ofAe. albopictus,a Major Worldwide Human Disease Vector

“…Clusters 17 through 19 correspond to blood-fed female ovaries and include genes enriched for cellular response to stimulus and Ras protein signal transduction which are important means of communication during the processes of oocyte and eggshell patterning (Dana et al 2005). In addition, several metabolism processes that are crucial for the breakdown of organic molecules such as deoxyribonucleotides are crucial to support cell division (Telang et al 2013). Finally, cluster 20 corresponds to the genes that are expressed in PBM female carcasses.…”

dsRNA uptake and persistence account for tissue‐dependent susceptibility to RNA interference in the migratory locust, Locusta migratoria

“…Tissue‐dependent sensitivity to RNAi has been observed in a number of insect species. In the mosquito Anopheles gambiae , salivary glands show a relatively lower response to RNAi than other tissues (Boisson et al ., ), while in the mosquito Aedes aegypti , the head and ovary appear to be less responsive to RNAi compared with the fat body, midgut and abdomen (Telang et al ., ). In lepidopteran species, more success of RNAi and higher knockdown efficiency have been seen in pheromone glands and silk glands, followed by the fat body, haemocytes, midgut and brain, whereas wing discs and larval epidermis seem to be insensitive (Terenius et al ., ).…”