Determination in oocytes of the reproductive modes for the brine shrimp Artemia parthenogenetica.
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.
Dai
Zhong-Min
ZM
Institute of Cell Biology and Genetics, Zhejiang University, Hangzhou, China.
Li
Ran
R
Dai
Li
L
Yang
Jin-Shu
JS
Chen
Su
S
Zeng
Qing-Guo
QG
Yang
Fan
F
Yang
Wei-Jun
WJ
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
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