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Exploring the transcriptome of ovarian follicles of Rhodnius prolixus
Medeiros MN1, Paiva-Silva GO2,
Capurro ML3, Masuda H4, Machado EA1
1- Laboratório de Entomologia Médica, IBCCF, UFRJ
2- Laboratório de Bioquímica de Artrópodos Hematófagos, IBqM, UFRJ
3- Laboratório de Mosquitos Geneticamente Modificados, ICBII, USP
4-Laboratório de Bioquímica de Insetos, IBqM, UFRJ
Insects are among the most numerous classes of organisms on Earth, colonizing almost all niches. It is due at least in part to their efficient reproductive strategy, comprising the generation of large offspring in a short period of time.
Insect oogenesis is a highly coordinated process consisting mainly in the incorporation of proteins synthesized in the fat body (a biosynthetic organ analog of liver and adipose tissue in vertebrates) to ovarian follicles. Despite the enormous number of species and their importance as human disease vectors or crop plagues, the mechanisms comprising their reproduction, mainly at the molecular level, are still poorly understood.
The objective in this work is to describe genes being transcribed in ovarian follicles on diverse developmental stages from the blood-sucking bug Rhodnius prolixus (Hemiptera: Reduviidae), an important vector of Chagas' disease and a classical model of insect oogenesis.
Ovaries of adult mated females were dissected and isolated follicles were submitted to mRNA extraction. This RNA was used to the construction of a cDNA library using a SMARTTMcDNA Library Construction Kit (ClonTech Laboratories) followig manufacturer's instructions. The transcriptome was made by random sequencing about 1200 clones from the resulting library on a ABI 377 sequencer using BigDye v3.0 Terminator Cycle Sequencing kit (Applied Biosystems, CA, EUA). Resulting sequences were checked for quality and analyzed for sequence similarity by submitting to different databases.
Rhodnius follicle tanscriptome showed, as expected, a large quantity of mRNAs for ribossomal proteins, and many clones with no similarty to any known protein (insect sequences are little abundant in databases, and still less sequences are referred to the Hemipteran order). Despite that, we found many sequences related to ovogenesis and embryogenesis in other species and also related to Anopheles gambiae, another blood-sucking insect. The ongoing Rhodnius prolixus genome project and further analysis extending the number of clones sequenced may bring light to our follicle transcriptome.
Supported by CNPq, FAPERJ and PRONEX.
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