title: The Jumonji gene family in Crassostrea gigas suggests evolutionary conservation of Jmj-C histone demethylases orthologues in the oyster gametogenesis and development.
abstract: Jumonji (Jmj) proteins are histone demethylases, which control the identity of stem cells. Jmj genes were characterized from plants to mammals where they have been implicated in the epigenetic regulation of development. Despite the Pacific oyster Crassostrea gigas representing one of the most important aquaculture resources worldwide, the molecular mechanisms governing the embryogenesis and reproduction of this lophotrochozoan species remain poorly understood. However, annotations in the C. gigas EST library suggested the presence of putative Jumonji genes, raising the question of the conservation of this family of histone demethylases in the oyster. Using Primer walking, 5'-RACE PCR and in silico analyses, we characterized nine Jumonji orthologues in the oyster, called Cg-Jmj, bearing conserved domains critical for putative histone demethylase activity. Phylogenic analyses revealed that oyster Jumonji cluster into two distinct groups: 'single-domain Jmj' and 'multi-domain Jmj', and define 8 subgroups corresponding to each cognate orthologues in metazoans. RT-qPCR investigations showed specific regulations of Cg-Jmj mRNAs during the early development and along the reproduction cycle. Furthermore, in situ and in toto hybridizations indicate that oyster Jumonji genes are transcribed mostly within the gonad in adult oysters whereas they display a ubiquitous expression during embryonic and larval development. Our study demonstrates the presence of nine Jumonji orthologues in the oyster C. gigas. Their domain conservation and their expression profile suggest an implication during reproduction and development, questioning about the epigenetic regulation by histone methylation in lophotrochozoans.
authors.affiliation: Université de Caen Basse-Normandie, Biologie des organismes marins et des écosystèmes associés (BioMEA) Esplanade de la paix, 14032 Caen Cedex, France; CNRS INEE FRE 3484, BioMEA, France.
authors.forename: Alexandre
authors.initials: A
authors.lastname: Fellous
authors.affiliation: Université de Caen Basse-Normandie, Biologie des organismes marins et des écosystèmes associés (BioMEA) Esplanade de la paix, 14032 Caen Cedex, France; CNRS INEE FRE 3484, BioMEA, France.
authors.forename: Pascal
authors.initials: P
authors.lastname: Favrel
authors.affiliation: Haskin Shellfish Research Laboratory, Institute of Marine and Coastal Sciences, Rutgers University, 6959 Miller Avenue, Port Norris, NJ 08349, USA.
authors.forename: Ximing
authors.initials: X
authors.lastname: Guo
authors.affiliation: Université de Caen Basse-Normandie, Biologie des organismes marins et des écosystèmes associés (BioMEA) Esplanade de la paix, 14032 Caen Cedex, France; CNRS INEE FRE 3484, BioMEA, France. Electronic address: guillaume.riviere@unicaen.fr.
authors.forename: Guillaume
authors.initials: G
authors.lastname: Riviere
mesh_terms: D000818:Animals; D001483:Base Sequence; D017124:Conserved Sequence; D049896:Crassostrea / Q000196:embryology / Q000201:enzymology / Q000235:genetics* / Q000502:physiology; D019143:Evolution, Molecular; D005718:Gametogenesis; D018507:Gene Expression Regulation, Developmental; D056484:Jumonji Domain-Containing Histone Demethylases / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D008969:Molecular Sequence Data; D005810:Multigene Family; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism
chemical_list: D012333:RNA, Messenger; D056484:Jumonji Domain-Containing Histone Demethylases
keywords: Development; Epigenetics; Histone; Jumonji; Methylation; Oyster; Reproduction