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| Status |
Public on Dec 06, 2010 |
| Title |
Geminin-regulated genes in the Xenopus laevis embryonic ectoderm |
| Organism |
Xenopus laevis |
| Experiment type |
Expression profiling by array
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| Summary |
Geminin cooperates with Polycomb to restrain multi-lineage commitment in the early embryo: Transient maintenance of a pluripotent embryonic cell population followed by the onset of multi-lineage commitment is a fundamental aspect of development. However, molecular regulation of this transition is not well characterized in vivo. Here we demonstrate that the nuclear protein Geminin is required to restrain commitment and spatially restrict mesoderm, endoderm, and non-neural ectoderm to their proper locations in the Xenopus embryo. We used microarray analyses to demonstrate that Geminin overexpression represses many genes associated with cell commitment and differentiation, while elevating expression levels of genes that maintain pluripotent early and immature neurectodermal cell states. We characterized Geminin’s relationship to cell signaling and found that Geminin broadly represses Activin-, FGF-, and BMP-mediated cell commitment. Conversely, Geminin knockdown enhances commitment responses to growth factor signaling and causes ectopic mesodermal, endodermal, and epidermal fate commitment in the embryo. We also characterized Geminin’s functional relationship with transcription factors that had similar activities and found that Geminin represses commitment independent of Oct4 ortholog (Oct25/60) activities, but depends upon intact Polycomb repressor function. Consistent with this, chromatin immunoprecipitation assays directed at mesodermal genes demonstrate that Geminin promotes Polycomb binding and Polycomb-mediated repressive histone modifications, while inhibiting modifications associated with gene activation. This work defines Geminin as an essential regulator of the embryonic transition from pluripotency through early multi-lineage commitment, and demonstrates that functional cooperativity between Geminin and Polycomb contributes to this process.
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| Overall design |
For each experiment, paired Geminin-injected versus uninjected samples were used for probe synthesis and hybridization to Affymetrix Xenopus laevis genome v1.0 arrays (Washington University Genechip facility). For each sample type (Geminin stage 10.5 and 12), the entire experiment (microinjection, RNA extraction, and microarray analysis) was repeated three times; the three microarray datasets resulting from these experiments were then compared (see Supplementary files).
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| Contributor(s) |
Kroll KL, Lim J, Hummert P, Mills JC |
| Citation(s) |
21098561 |
| Submission date |
Nov 05, 2010 |
| Last update date |
Mar 22, 2012 |
| Contact name |
Kristen L Kroll |
| E-mail(s) |
kkroll@wustl.edu
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| Organization name |
Washington University School of Medicine
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| Department |
Developmental Biology
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| Lab |
Kristen Kroll
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| Street address |
320 McDonnell Sciences/660 S. Euclid Ave.
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| City |
Saint Louis |
| State/province |
MO |
| ZIP/Postal code |
63110 |
| Country |
USA |
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| Platforms (1) |
| GPL1318 |
[Xenopus_laevis] Affymetrix Xenopus laevis Genome Array |
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| Samples (12)
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| Relations |
| BioProject |
PRJNA134347 |
| Supplementary file |
Size |
Download |
File type/resource |
| GSE25158_RAW.tar |
24.2 Mb |
(http)(custom) |
TAR (of CEL) |
| Processed data included within Sample table |
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