title: Modulation in the mRNA expression of ecdysone receptor gene in aquatic midge, Chironomus riparius upon exposure to nonylphenol and silver nanoparticles.
abstract: Chironomus riparius, a non-biting midge (Chironomidae, Diptera), is extensively used as a model organism in aquatic ecotoxicological studies, although little is known about its genome sequences. Ecdysteroids are steroid hormones that play an important role in development, growth, moulting of larva, and reproduction in Chironomus spp. The effect of ecdysteroids is mediated by their binding to the ecdysteroid receptor (EcR). To study the effect of environmental stressors, nonylphenol and silver nanoparticles (AgNPs), on the modulation of EcR mRNA, in this study, full length cDNA of C. riparius ecdysone receptor (CrEcR) was identified from the Expressed Sequence Tags (ESTs) database and expression of the corresponding mRNA was analyzed following exposure to nonylphenol and AgNPs. The CrEcR cDNA was 2548 base pairs (bp) in length, with a 5' untranslated region (UTR) of 242 bp and a 3' UTR of 684 bp. The open reading frame contains 1617 nucleotides, encoding 539 amino acids with a predicted molecular weight of 61 kDa and pI of 5.89, and revealed the presence of several domains associated with DNA binding, dimerization, ligand binding and transcriptional activation characteristic of steroid receptor family members. It was found that the expression level of CrEcR was significantly up-regulated on exposure to nonylphenol and significant up or down regulation was observed on exposure to AgNPs. These finding shows that nonylphenol as well as AgNPs could modulate the ecdysone nuclear receptor and may have significant implications in different developmental stages in C. riparius.
authors.affiliation: School of Environmental Engineering and Graduate School of Energy and Environmental System Engineering, University of Seoul, 90 Jeonnong-dong, Dongdaemun-gu, Seoul 130-743, Republic of Korea.
authors.forename: Prakash M Gopalakrishnan
authors.initials: PM
authors.lastname: Nair
authors.forename: Jinhee
authors.initials: J
authors.lastname: Choi
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002683:Chironomidae / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D004440:Ecdysone / Q000378:metabolism; D020224:Expressed Sequence Tags; D015870:Gene Expression / Q000187:drug effects; D007814:Larva / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D053768:Metal Nanoparticles / Q000737:chemistry*; D008969:Molecular Sequence Data; D016366:Open Reading Frames; D010636:Phenols / Q000494:pharmacology*; D010802:Phylogeny; D012333:RNA, Messenger / Q000378:metabolism*; D011987:Receptors, Steroid / Q000145:classification / Q000235:genetics / Q000378:metabolism*; D016415:Sequence Alignment; D012834:Silver / Q000737:chemistry / Q000494:pharmacology*
chemical_list: D010636:Phenols; D012333:RNA, Messenger; D011987:Receptors, Steroid; C055469:ecdysone receptor; D004440:Ecdysone; D012834:Silver; C025256:nonylphenol