TY - JOUR
T1 - Conservation of large foci formation in arrested oocytes of Caenorhabditis nematodes
AU - Jud, Molly
AU - Razelun, Jamie
AU - Bickel, Jeremy
AU - Czerwinski, Mike
AU - Schisa, Jennifer A.
N1 - Funding Information:
Acknowledgements We thank Cordell DeMattei for critical reading of the manuscript. MEX-3 antibodies were a gift from J. Priess. We thank Alex Kostin and Emily Petty for assistance with confocal microscopy. J.A.S. is supported by a grant from the NIH, R15 GM078157-01. Stocks were obtained from the C. elegans Genetics Stock Center that is funded by the NIH.
PY - 2007/3
Y1 - 2007/3
N2 - Within the rhabditid phylogeny of nematodes, the great majority of species are gonochoristic, having evolved as obligate male/female species. In contrast, the well-studied nematode model system, Caenorhabditis elegans, is androdioecious, utilizing a hermaphroditic/ male reproductive system. We have previously determined that in the arrested oocytes of old-aged C. elegans hermaphrodites with depleted sperm, large cytoplasmic ribonucleoprotein foci form. The formation of these foci is reversible, as they dissociate within 3 h after a male mates with the hermaphrodite, resupplying it with sperm. The functional significance of these oocyte foci is not known and previously has not been clear for a hermaphroditic species in which oocytes of young adults wait only approximately 23 min to be fertilized. One hypothesis is that the foci function to maintain maternal mRNAs in oocytes while fertilization is delayed. In this paper, we examine four gonochoristic rhabditid species: Caenorhabditis remanei, Caenorhabditis sp. CB5161, Caenorhabditis sp. PS1010, and Rhabditella axei DF5006. We demonstrate that in three of these four species, ovulation arrests in unmated females until mating occurs and large cytoplasmic foci develop in arrested oocytes. The oocyte foci contain nuclear pore proteins and, in C. remanei at least, the RNA-binding protein MEX-3 as well as RNA. We speculate that these foci maintain the integrity of ooctyes, possibly maintaining the stability or translational repression of maternal mRNAs in unmated females. We further speculate that their presence in oocytes of old-aged C. elegans hermaphrodites is due to conservation from an ancestral gonochoristic state.
AB - Within the rhabditid phylogeny of nematodes, the great majority of species are gonochoristic, having evolved as obligate male/female species. In contrast, the well-studied nematode model system, Caenorhabditis elegans, is androdioecious, utilizing a hermaphroditic/ male reproductive system. We have previously determined that in the arrested oocytes of old-aged C. elegans hermaphrodites with depleted sperm, large cytoplasmic ribonucleoprotein foci form. The formation of these foci is reversible, as they dissociate within 3 h after a male mates with the hermaphrodite, resupplying it with sperm. The functional significance of these oocyte foci is not known and previously has not been clear for a hermaphroditic species in which oocytes of young adults wait only approximately 23 min to be fertilized. One hypothesis is that the foci function to maintain maternal mRNAs in oocytes while fertilization is delayed. In this paper, we examine four gonochoristic rhabditid species: Caenorhabditis remanei, Caenorhabditis sp. CB5161, Caenorhabditis sp. PS1010, and Rhabditella axei DF5006. We demonstrate that in three of these four species, ovulation arrests in unmated females until mating occurs and large cytoplasmic foci develop in arrested oocytes. The oocyte foci contain nuclear pore proteins and, in C. remanei at least, the RNA-binding protein MEX-3 as well as RNA. We speculate that these foci maintain the integrity of ooctyes, possibly maintaining the stability or translational repression of maternal mRNAs in unmated females. We further speculate that their presence in oocytes of old-aged C. elegans hermaphrodites is due to conservation from an ancestral gonochoristic state.
KW - Mating system
KW - Nematode
KW - Oocyte
KW - Ovulation
KW - Ribonucleoprotein
UR - http://www.scopus.com/inward/record.url?scp=33847632884&partnerID=8YFLogxK
U2 - 10.1007/s00427-006-0130-3
DO - 10.1007/s00427-006-0130-3
M3 - Article
C2 - 17216268
AN - SCOPUS:33847632884
SN - 0949-944X
VL - 217
SP - 221
EP - 226
JO - Development Genes and Evolution
JF - Development Genes and Evolution
IS - 3
ER -