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Development
2011 Jan 01;1382:237-43. doi: 10.1242/dev.054940.
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Small micromeres contribute to the germline in the sea urchin.
Yajima M
,
Wessel GM
.
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Many indirect developing animals create specialized multipotent cells in early development to construct the adult body and perhaps to hold the fate of the primordial germ cells. In sea urchin embryos, small micromeres formed at the fifth division appear to be such multipotent cells: they are relatively quiescent in embryos, but contribute significantly to the coelomic sacs of the larvae, from which the major tissues of the adult rudiment are derived. These cells appear to be regulated by a conserved gene set that includes the classic germline lineage genes vasa, nanos and piwi. In vivo lineage mapping of the cells awaits genetic manipulation of the lineage, but previous research has demonstrated that the germline is not specified at the fourth division because animals are fertile even when micromeres, the parent blastomeres of small micromeres, are deleted. Here, we have deleted small micromeres at the fifth division and have raised the resultant larvae to maturity. These embryos developed normally and did not overexpress Vasa, as did embryos from a micromere deletion, implying the compensatory gene regulatory network was not activated in small micromere-deleted embryos. Adults from control and micromere-deleted embryos developed gonads and visible gametes, whereas small micromere-deleted animals formed small gonads that lacked gametes. Quantitative PCR results indicate that small micromere-deleted animals produce background levels of germ cell products, but not specifically eggs or sperm. These results suggest that germline specification depends on the small micromeres, either directly as lineage products, or indirectly by signaling mechanisms emanating from the small micromeres or their descendants.
Bendel-Stenzel,
The origin and migration of primordial germ cells in the mouse.
1998, Pubmed
Bendel-Stenzel,
The origin and migration of primordial germ cells in the mouse.
1998,
Pubmed
Cameron,
Lineage and fate of each blastomere of the eight-cell sea urchin embryo.
1987,
Pubmed
,
Echinobase
Cameron,
Macromere cell fates during sea urchin development.
1991,
Pubmed
,
Echinobase
Cox,
A novel class of evolutionarily conserved genes defined by piwi are essential for stem cell self-renewal.
1998,
Pubmed
Duboc,
Left-right asymmetry in the sea urchin embryo is regulated by nodal signaling on the right side.
2005,
Pubmed
,
Echinobase
Ettensohn,
Cell lineage conversion in the sea urchin embryo.
1988,
Pubmed
,
Echinobase
Extavour,
Mechanisms of germ cell specification across the metazoans: epigenesis and preformation.
2003,
Pubmed
Forbes,
Nanos and Pumilio have critical roles in the development and function of Drosophila germline stem cells.
1998,
Pubmed
Gustafson,
Post-translational regulation by gustavus contributes to selective Vasa protein accumulation in multipotent cells during embryogenesis.
2011,
Pubmed
,
Echinobase
HORSTADIUS,
The mechanics of sea urchin development.
1950,
Pubmed
,
Echinobase
Huang,
Autosomal XX sex reversal caused by duplication of SOX9.
1999,
Pubmed
Illmensee,
Transplantation of posterior polar plasm in Drosophila. Induction of germ cells at the anterior pole of the egg.
1974,
Pubmed
Juliano,
Nanos functions to maintain the fate of the small micromere lineage in the sea urchin embryo.
2010,
Pubmed
,
Echinobase
Juliano,
Developmental biology. Versatile germline genes.
2010,
Pubmed
Juliano,
Germ line determinants are not localized early in sea urchin development, but do accumulate in the small micromere lineage.
2006,
Pubmed
,
Echinobase
Juliano,
An evolutionary transition of Vasa regulation in echinoderms.
2009,
Pubmed
,
Echinobase
Juliano,
A conserved germline multipotency program.
2010,
Pubmed
,
Echinobase
Kobayashi,
Essential role of the posterior morphogen nanos for germline development in Drosophila.
1996,
Pubmed
Kugler,
Regulation of Drosophila vasa in vivo through paralogous cullin-RING E3 ligase specificity receptors.
2010,
Pubmed
Kurihara,
Developmental potential of small micromeres in sea urchin embryos.
2005,
Pubmed
,
Echinobase
Lasko,
The product of the Drosophila gene vasa is very similar to eukaryotic initiation factor-4A.
1988,
Pubmed
Lasko,
Posterior localization of vasa protein correlates with, but is not sufficient for, pole cell development.
1990,
Pubmed
Oliveri,
Global regulatory logic for specification of an embryonic cell lineage.
2008,
Pubmed
,
Echinobase
Pehrson,
The fate of the small micromeres in sea urchin development.
1986,
Pubmed
,
Echinobase
Ransick,
A complete second gut induced by transplanted micromeres in the sea urchin embryo.
1993,
Pubmed
,
Echinobase
Ransick,
Micromeres are required for normal vegetal plate specification in sea urchin embryos.
1995,
Pubmed
,
Echinobase
Ransick,
Postembryonic segregation of the germ line in sea urchins in relation to indirect development.
1996,
Pubmed
,
Echinobase
Raz,
The function and regulation of vasa-like genes in germ-cell development.
2000,
Pubmed
Salinas,
The DEAD box RNA helicase VBH-1 is required for germ cell function in C. elegans.
2007,
Pubmed
Seydoux,
Pathway to totipotency: lessons from germ cells.
2006,
Pubmed
Shirae-Kurabayashi,
Dynamic redistribution of vasa homolog and exclusion of somatic cell determinants during germ cell specification in Ciona intestinalis.
2006,
Pubmed
Styhler,
vasa is required for GURKEN accumulation in the oocyte, and is involved in oocyte differentiation and germline cyst development.
1998,
Pubmed
Sulston,
The embryonic cell lineage of the nematode Caenorhabditis elegans.
1983,
Pubmed
Suzuki,
Functional redundancy among Nanos proteins and a distinct role of Nanos2 during male germ cell development.
2007,
Pubmed
Tanaka,
The mouse homolog of Drosophila Vasa is required for the development of male germ cells.
2000,
Pubmed
Tanaka,
Study of the Lineage and Cell Cycle of Small Micromeres in Embryos of the Sea Urchin, Hemicentrotus pulcherrimus: (small micromeres/cell cycle/cell lineage/unequal cleavage/sea urchin).
1990,
Pubmed
,
Echinobase
Tomancak,
Oocyte polarity depends on regulation of gurken by Vasa.
1998,
Pubmed
Tsuda,
Conserved role of nanos proteins in germ cell development.
2003,
Pubmed
Voronina,
Vasa protein expression is restricted to the small micromeres of the sea urchin, but is inducible in other lineages early in development.
2008,
Pubmed
,
Echinobase
Wang,
Nanos maintains germline stem cell self-renewal by preventing differentiation.
2004,
Pubmed
Wong,
Major components of a sea urchin block to polyspermy are structurally and functionally conserved.
2004,
Pubmed
,
Echinobase
Yajima,
Evolutionary modification of mesenchyme cells in sand dollars in the transition from indirect to direct development.
2007,
Pubmed
,
Echinobase
Yajima,
A switch in the cellular basis of skeletogenesis in late-stage sea urchin larvae.
2007,
Pubmed
,
Echinobase