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SRP029742
Zea mays
64 Downloadable Samples
Illumina HiSeq 2000
Description
Heterosis which is the improved vigor of F1-hybrids compared to their parents is widely exploited in maize (Zea mays L.) breeding to produce elite hybrids of superior yield. The transcriptomes of the maize inbred lines B73 and Mo17 and their reciprocal hybrid offspring were surveyed in the meristematic zone, the elongation zone, cortex and stele tissues of primary roots, prior to the developmental manifestation of heterosis. Single parent expression (SPE) is consistent with the dominance model for heterosis in that it denotes genes that are expressed in only one parent but in both reciprocal hybrids. In primary root tissues, between 1,027 (elongation zone) and 1,206 (stele) SPE patterns were observed. As a consequence, hybrids displayed in each tissue >400 active genes more than either parent. Analysis of tissue-specific SPE dynamics revealed that 1,233 of 2,233 SPE genes displayed SPE in all tissues in which they were expressed while 1,000 SPE genes displayed in at least one tissue a non-SPE pattern. In addition, 64% (17,351/ 27,164) of all expressed genes were assigned to the two subgenomes which are the result of an ancient genome duplication. By contrast, only between 18 and 25% of the SPE genes were assigned to a subgenome suggesting that a disproportionate number of SPE genes are evolutionary young and emerged after genome duplication. We hypothesize that this phenomenon is associated with human selection of favorable maize genotypes which might primarily affect younger genes rather than genes whose functions have been conserved for millions of years.
Publication Title
Nonsyntenic genes drive highly dynamic complementation of gene expression in maize hybrids.
Sample Metadata Fields
No sample metadata fields
View Samples- Mus musculus
- 7 Downloadable Samples
Affymetrix Mouse Gene 2.0 ST Array (mogene20st)
Description
Cellular reprogramming from somatic cells to induced pluripotent stem cells (iPSCs) can be achieved through forced expression of the transcription factors Oct4, Klf4, Sox2 and c-Myc (OKSM). These factors, in combination with environmental cues, induce a stable intrinsic pluripotency network that confers indefinite self-renewal capacity on iPSCs. In addition to Oct4 and Sox2, the homeodomain-containing transcription factor Nanog is an integral part of the pluripotency network. Although Nanog expression is not required for the maintenance of pluripotent stem cells, it has been reported to be essential for the establishment of both embryonic stem cells (ESCs) from blastocysts and iPSCs from somatic cells. Here we revisit the role of Nanog in direct reprogramming. Surprisingly, we find that Nanog is dispensable for iPSC formation under optimized culture conditions. We further document that Nanog-deficient iPSCs are transcriptionally highly similar to wild-type iPSCs and support the generation of teratomas and chimeric mice. Lastly, we provide evidence that the presence of ascorbic acid in the culture media is critical for overcoming the previously observed reprogramming block of Nanog knockout cells.
Publication Title
Nanog is dispensable for the generation of induced pluripotent stem cells.
Sample Metadata Fields
Specimen part
View Samples- Homo sapiens
- 19 Downloadable Samples
- Affymetrix Human Genome U133 Plus 2.0 Array (hgu133plus2)
Description
Direct reprogramming of human fibroblasts to a pluripotent state has been achieved through ectopic expression of the transcription factors OCT4, SOX2, and either cMYC and KLF4 or NANOG and LIN28. Little is known, however, about the mechanisms by which reprogramming occurs, which is in part limited by the low efficiency of conversion. To this end, we sought to create a doxycycline-inducible lentiviral system to convert primary human fibroblasts and keratinocytes into human induced pluripotent stem (hiPS) cells. hiPS cells generated with this system were molecularly and functionally similar to human embryonic stem (hES) cells, demonstrated by gene expression profiles, DNA methylation status, and differentiation potential. While expression of the viral transgenes was required for several weeks in fibroblasts, we found that 10 days was sufficient for the reprogramming of keratinocytes, suggesting that the kinetics of reprogramming are cell-type dependent. Using our inducible system, we developed a strategy to induce hiPS cell formation at high frequency by generating differentiated cells that contain the viral transgenes in a pattern that enables successful induction of pluripotency. Upon addition of doxycycline to differentiated hiPS-derived cells, we obtained secondary hiPS cells at a frequency at least 100-fold greater than the initial conversion. The ability to reprogram cells with high efficiency provides a unique platform to dissect the underlying molecular and biochemical processes that accompany nuclear reprogramming.
Publication Title
A high-efficiency system for the generation and study of human induced pluripotent stem cells.
Sample Metadata Fields
No sample metadata fields
View Samples- Mus musculus
- 11 Downloadable Samples
- Affymetrix Mouse Gene 2.0 ST Array (mogene20st)
Description
The reprogramming of somatic cells into induced pluripotent stem cells (iPSCs) upon overexpression of OCT4, KLF4, SOX2 and c-MYC (OKSM) provides a powerful system to interrogate basic mechanisms of cell fate change. However, iPSC formation with standard methods is typically protracted and inefficient, resulting in heterogeneous cell populations. We show that exposure of OKSM-expressing cells to both ascorbic acid and a GSK3- inhibitor (AGi) facilitates more synchronous and rapid iPSC formation from several mouse cell types. AGi treatment restored the ability of refractory cell populations to yield iPSC colonies, and it attenuated the activation of developmental regulators commonly observed during the reprogramming process. Moreover, AGi supplementation gave rise to chimera-competent iPSCs after as little as 48 h of OKSM expression. Our results offer a simple modification to the reprogramming protocol, facilitating iPSC induction at unparalleled efficiencies and enabling dissection of the underlying mechanisms in more homogeneous cell populations.
Publication Title
Small molecules facilitate rapid and synchronous iPSC generation.
Sample Metadata Fields
Specimen part, Treatment, Time
View Samples- Mus musculus
- 61 Downloadable Samples
Affymetrix Mouse Genome 430 2.0 Array (mouse4302), Affymetrix HT Mouse Genome 430A Array (htmg430a)
Description
This SuperSeries is composed of the SubSeries listed below.
Publication Title
Aberrant silencing of imprinted genes on chromosome 12qF1 in mouse induced pluripotent stem cells.
Sample Metadata Fields
Specimen part
View Samples- Mus musculus
- 57 Downloadable Samples
- Affymetrix Mouse Genome 430 2.0 Array (mouse4302), Affymetrix HT Mouse Genome 430A Array (htmg430a)
Description
Induced pluripotent stem cells (iPSCs) can be generated by enforced expression of defined transcription factors in somatic cells. It remains controversial whether iPSCs are equivalent to blastocyst-derived embryonic stem cells (ESCs). Using genetically matched cells, we found that the overall mRNA expression patterns of these cell types are indistinguishable with the exception of a few transcripts encoded on chromosome 12qF1.
Publication Title
Aberrant silencing of imprinted genes on chromosome 12qF1 in mouse induced pluripotent stem cells.
Sample Metadata Fields
Specimen part
View Samples- Rattus norvegicus
- 12 Downloadable Samples
- Affymetrix Rat Gene 1.0 ST Array (ragene10st)
Description
Autosomal recessive polycystic kidney disease is a severe, monogenetically inherited kidney and liver disease and PCK rats carrying the orthologous mutant gene serve as a model of human disease. We combined selective MALDI imaging of sulfated kidney lipids and Fisher discriminant analysis of imaging data sets for identification of candidate lipid markers of progressive disease in PCK rats. Our study highlights strong increases in lower mass lipids as main classifiers of cystic disease. Structure determination by high resolution mass spectrometry identifies these altered lipids as taurine-conjugated bile acids. Beside increased levels of serum-cholesterol these sulfated lipids are selectively elevated in the PCK rat model but not in models of related hepatorenal fibrocystic diseases suggesting that they be molecular markers of the disease.
Publication Title
MALDI imaging MS reveals candidate lipid markers of polycystic kidney disease.
Sample Metadata Fields
Sex, Age, Specimen part, Disease, Disease stage
View Samples- Mus musculus
- 6 Downloadable Samples
- Illumina HiSeq 2000
Description
Herein, we demonstrated that the cell lineage commitment is unexpectedly regulated by the novel functions of H2A.X, a histone variant which was only well-known for its role in genome integrity maintenance previously. Surprisingly, only in ESCs but not differentiated cells, H2A.X is specifically targeted to genomic regions encoding early embryonic and extra-embryonic lineage genes to repress their expression. In addition, H2A.X is also enriched at genomic regions sensitive to replication stress and maintains genomic stability thereat. Most interestingly, faithful H2A.X deposition plays critical roles in maintaining both cell lineage commitment and genome integrity in iPSC. In iPSC lines which support the development of "all-iPS" animals, H2A.X deposition faithfully recapitulates the ESC pattern and therefore, the genome stability and cell lineage commitment are maintained. In iPSC lines that fail to support embryonic development, defective H2A.X depositions result in aberrant upregulation of early embryonic and extra-embryonic lineage genes and H2A.X-dependent genome instability. Overall design: mRNA-Seq of WT ESC and H2A.X KO ESC; and 4N+, 4N- iPSC.
Publication Title
Histone variant H2A.X deposition pattern serves as a functional epigenetic mark for distinguishing the developmental potentials of iPSCs.
Sample Metadata Fields
Specimen part, Subject
View Samples- Mus musculus
- 5 Downloadable Samples
- Affymetrix Mouse Gene 2.0 ST Array (mogene20st)
Description
Brief expression of pluripotency-associated factors such as Oct4, Klf4, Sox2 and c-Myc (OKSM), in combination with differentiation-inducing signals, has been reported to trigger transdifferentiation of fibroblasts into other cell types. Here we show that OKSM expression in mouse fibroblasts gives rise to both induced pluripotent stem cells (iPSCs) and induced neural stem cells (iNSCs) under conditions previously shown to induce only iNSCs. Fibroblast-derived iNSC colonies silenced retroviral transgenes and reactivated silenced X chromosomes, both hallmarks of pluripotent stem cells. Moreover, lineage tracing with an Oct4-CreER labeling system demonstrated that virtually all iNSC colonies originated from cells transiently expressing Oct4, whereas ablation of Oct4+ cells prevented iNSC formation. Lastly, an alternative transdifferentiation cocktail that lacks Oct4 and was reportedly unable to support induced pluripotency yielded iPSCs and iNSCs carrying the Oct4-CreER-derived lineage label. Together, these data suggest that iNSC generation from fibroblasts using OKSM and other pluripotency-related reprogramming factors requires passage through a transient iPSC state.
Publication Title
Lineage conversion induced by pluripotency factors involves transient passage through an iPSC stage.
Sample Metadata Fields
Sex, Specimen part
View Samples- Mus musculus
- 4 Downloadable Samples
- Affymetrix Mouse Genome 430 2.0 Array (mouse4302)
Description
Pluripotent cells can be derived from somatic cells by either overexpression of defined transcription factors (resulting in induced pluripotent stem cells (iPSCs)) or by nuclear transfer or cloning (resulting in NT-ESCs). To determine whether cloning further reprograms iPSCs, we used iPSCs as donor cells in nuclear transfer experiments.
Publication Title
Aberrant silencing of imprinted genes on chromosome 12qF1 in mouse induced pluripotent stem cells.
Sample Metadata Fields
Specimen part
View Samples