title: Significant fluctuations in ecdysteroid receptor gene (EcR) expression in relation to seasons of molt and reproduction in the grapsid crab, Metopograpsus messor (Brachyura: Decapoda).
abstract: Metopograpsus messor, a brachyuran crab inhabiting the estuaries of North Kerala (India), is a prolific breeder releasing approximately 14-16 broods a year. The present paper reports the sequence information on the DNA binding domain (C domain, DBD), linker (D domain) and ligand binding domain (E domain, LBD) of M. messor ecdysteroid receptor (MmEcR) gene, the first grapsid brachyuran crab EcR examined. We have also measured MmEcR transcript levels in the ovary and the hepatopancreas throughout the annual cycle, with special reference to seasons of molt and reproduction. MmEcR expression in both the tissues is found to be at its peak (P<0.05) in late premolt crabs (January/May, molt/reproduction season); the expression levels are lowest (P<0.05) during June/July, when the females would neither molt nor reproduce (season for molt/reproduction repose). Intermediate levels of expression were found during the breeding season (August/December). Interestingly, this pattern of gene expression is in concordance with the fluctuating ecdysteroid levels of the hemolymph and Y organ secretory activity. The significant levels of fluctuation in the ovarian expression of MmEcR strongly suggest the ovary as a potential target for ecdysteroid action. A season-wise comparison of the gene expression reveals that ovarian MmEcR transcript levels are higher in breeding crabs (August/December) than the non-breeding animals (June/July), implicating a possible ecdysteroid role in reproduction in M. messor.
authors.affiliation: School of Biosciences & Technology, VIT University, Vellore, 632014 Tamil Nadu, India.
authors.forename: Sharmishtha
authors.initials: S
authors.lastname: Shyamal
authors.affiliation: School of Biosciences & Technology, VIT University, Vellore, 632014 Tamil Nadu, India. Electronic address: gopianilkumar@gmail.com.
authors.forename: G
authors.initials: G
authors.lastname: Anilkumar
authors.affiliation: School of Biosciences & Technology, VIT University, Vellore, 632014 Tamil Nadu, India.
authors.forename: R
authors.initials: R
authors.lastname: Bhaskaran
authors.affiliation: School of Biosciences & Technology, VIT University, Vellore, 632014 Tamil Nadu, India.
authors.forename: G P
authors.initials: GP
authors.lastname: Doss
authors.affiliation: Department of Biology, University of Oklahoma, USA.
authors.forename: D S
authors.initials: DS
authors.lastname: Durica
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D003386:Brachyura / Q000235:genetics* / Q000502:physiology*; D003001:Cloning, Molecular; D026461:Ecdysteroids / Q000378:metabolism; D005260:Female; D018507:Gene Expression Regulation, Developmental; D006801:Humans; D008024:Ligands; D008958:Models, Molecular; D008969:Molecular Sequence Data; D018978:Molting / Q000235:genetics*; D010802:Phylogeny; D017434:Protein Structure, Tertiary; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D011987:Receptors, Steroid / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D012098:Reproduction / Q000235:genetics; D012621:Seasons; D016415:Sequence Alignment
chemical_list: D026461:Ecdysteroids; D008024:Ligands; D012333:RNA, Messenger; D011987:Receptors, Steroid; C034808:ecdysteroid receptor
keywords: 20HE; Ecdysteroid receptor; Metopograpsus messor; Molting; Reproduction