title: Determination in oocytes of the reproductive modes for the brine shrimp Artemia parthenogenetica.
abstract: The brine shrimp, Artemia, reproduces either oviparously, producing encysted embryos (diapause cysts), or ovoviviparously, producing free-swimming nauplii. Environmental factors, such as photoperiod, have been applied to control the reproduction mode of Artemia, but when the determination of a reproductive mode occurs remains unknown. We analysed the differential gene expression between oocytes from oviparous and ovoviviparous Artemia reared under different photoperiods. A total of 692 qualified cDNA clones were obtained by subtractive hybridization, 327 of which matched GenBank® Nucleotide Sequence Database entries. Gene expressions of 44 cDNAs (representing 56 clones) were analysed in oocytes using real-time PCR. Among these genes, 11 (21 clones) were significantly (P<0.05) up-regulated and 7 (9 clones) down-regulated in Artemia oocytes that subsequently enter diapause. Remarkably, known diapause-related proteins such as ArHsp22 (Artemia heat-shock protein 22) and chitin-binding proteins are found to be already differentially expressed. Furthermore, RNAi (RNA interference) knockdown of a differentially expressed gene, polo-like kinase 1, in oocyte of ovoviviparous Artemia led to the production of white embryos rather than free-swimming nauplii. In summary, our results provide evidence at the molecular level that the reproductive mode of Artemia is already determined at the oocyte stage of their life cycle.
authors.affiliation: Institute of Cell Biology and Genetics, Zhejiang University, Hangzhou, China.
authors.forename: Zhong-Min
authors.initials: ZM
authors.lastname: Dai
authors.forename: Ran
authors.initials: R
authors.lastname: Li
authors.forename: Li
authors.initials: L
authors.lastname: Dai
authors.forename: Jin-Shu
authors.initials: JS
authors.lastname: Yang
authors.forename: Su
authors.initials: S
authors.lastname: Chen
authors.forename: Qing-Guo
authors.initials: QG
authors.lastname: Zeng
authors.forename: Fan
authors.initials: F
authors.lastname: Yang
authors.forename: Wei-Jun
authors.initials: WJ
authors.lastname: Yang
mesh_terms: D000818:Animals; D001156:Artemia / Q000166:cytology / Q000196:embryology* / Q000235:genetics*; D018797:Cell Cycle Proteins / Q000235:genetics; D018076:DNA, Complementary / Q000235:genetics; D004625:Embryo, Nonmammalian / Q000196:embryology / Q000502:physiology; D018507:Gene Expression Regulation, Developmental / Q000235:genetics*; D006360:Heat-Shock Proteins / Q000235:genetics; D009865:Oocytes / Q000166:cytology / Q000378:metabolism*; D052287:Oviparity / Q000235:genetics; D052285:Ovoviviparity / Q000235:genetics; D017440:Photoperiod; D017346:Protein Serine-Threonine Kinases / Q000235:genetics; D011518:Proto-Oncogene Proteins / Q000235:genetics; D034622:RNA Interference / Q000502:physiology; D012098:Reproduction / Q000235:genetics*; D000097869:Polo-Like Kinase 1
chemical_list: D018797:Cell Cycle Proteins; D018076:DNA, Complementary; D006360:Heat-Shock Proteins; D017346:Protein Serine-Threonine Kinases; D011518:Proto-Oncogene Proteins; D000097869:Polo-Like Kinase 1