Journal Details


Volume Number:  14
Jurnal Name:  Efflatounia

Authors: 
               Azza Mohamed Elgendy1
               Mohamed Elmogy
               Makio Takeda

Title:
ECDYSONE RECEPTOR ISOFORM A (ECR-A): CLONING AND DEVELOPMENTAL EXPRESSION PATTERN DURING VITELLOGENESIS IN THE HEMIMETABOLOUS INSECT PERIPLANETA AMERICANA

Keywords: 
Ecdysone receptor (EcR), Vitellogenesis, Periplaneta americana, Female fat body, Expression pattern

Abstract:
The ecdysone receptor (EcR) regulates various cellular responses to ecdysteroids during insect development and adult life. Insects have multiple EcR isoforms with different N-terminal A/B domains that contain the isoform specific activation function (AF)-1 region. Although distinct physiological functions of the EcR isoforms have been characterized in higher holometabolous insects, they remain unclear in basal direct-developing insects, in which only A isoform has been identified. The molecular basis of ecdysone actions have been analysed in great detail in holometabolous insects such as fruit flies, mosquitoes, and moths, but rarely in primitive insects. The primitive hemimetabolous insect Periplaneta americana was used, as a model, to isolate and characterize the cDNAs of ecdysone receptor isoform-A (PamEcR-A) from the female fat body tissues. The cloned PamEcR-A includes an open reading frame of 1704 nucleotides that shares a high degree of homology with other insect EcR-A. To shed light on the role of PamEcR-A during adult female vitellogenesis, the tissues expression pattern of EcR-A was studied using semi-quantitative RT-PCR and it was found to be varied depending on tissue type. In adult female fat body, the transcript was abundant at all vitellogenic stages with high expression level at the end of vitellogenesis (day10). The PamEcR-A expression was quite different from the complex expression patterns of EcR isoforms observed in holometabolous insects during vitellogenesis. However, the EcR role in development may be similar in holometabolous and hemimetabolous insects, its vitellogenic role seemed to be different. The present work will pave the way for several other investigations to understand the ecdysteroid-dependent genetic hierarchy inhibiting vitellogenesis in the American cockroach.

Paper Pdf. File:
Paper Pdf. File
http://www.efflatounia.com/files/14 25-3.pdf