Pantakani, Dasaradha Venkata Krishna

[["dc.bibliographiccitation.artnumber","e22413"],["dc.bibliographiccitation.issue","7"],["dc.bibliographiccitation.journal","PLoS ONE"],["dc.bibliographiccitation.volume","6"],["dc.contributor.author","Xu, X."],["dc.contributor.author","Pantakani, Dasaradha Venkata Krishna"],["dc.contributor.author","Luehrig, Sandra"],["dc.contributor.author","Tan, Xiaoying"],["dc.contributor.author","Khromov, Tatjana"],["dc.contributor.author","Nolte, Jessica"],["dc.contributor.author","Dressel, Ralf"],["dc.contributor.author","Zechner, Ulrich"],["dc.contributor.author","Engel, Wolfgang"],["dc.date.accessioned","2018-11-07T08:54:13Z"],["dc.date.available","2018-11-07T08:54:13Z"],["dc.date.issued","2011"],["dc.description.abstract","Embryonic stem cells (ESCs) generated from the in-vitro culture of blastocyst stage embryos are known as equivalent to blastocyst inner cell mass (ICM) in-vivo. Though several reports have shown the expression of germ cell/pre-meiotic (GC/PrM) markers in ESCs, their functional relevance for the pluripotency and germ line commitment are largely unknown. In the present study, we used mouse as a model system and systematically analyzed the RNA and protein expression of GC/PrM markers in ESCs and found them to be comparable to the expression of cultured pluripotent cells originated from the germ line. Further, siRNA knockdown experiments have demonstrated the parallel maintenance and independence of pluripotent and GC/PrM networks in ESCs. Through chromatin immunoprecipitation experiments, we observed that pluripotent cells exhibit active chromatin states at GC marker genes and a bivalent chromatin structure at PrM marker genes. Moreover, gene expression analysis during the time course of iPS cells generation revealed that the expression of GC markers precedes pluripotency markers. Collectively, through our observations we hypothesize that the chromatin state and the expression of GC/PrM markers might indicate molecular parallels between in-vivo germ cell specification and pluripotent stem cell generation."],["dc.identifier.doi","10.1371/journal.pone.0022413"],["dc.identifier.isi","000293172900028"],["dc.identifier.pmid","21799849"],["dc.identifier.purl","https://resolver.sub.uni-goettingen.de/purl?gs-1/8198"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/22620"],["dc.notes.intern","Merged from goescholar"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Public Library Science"],["dc.relation.issn","1932-6203"],["dc.rights","CC BY 2.5"],["dc.rights.uri","https://creativecommons.org/licenses/by/2.5"],["dc.title","Stage-Specific Germ-Cell Marker Genes Are Expressed in All Mouse Pluripotent Cell Types and Emerge Early during Induced Pluripotency"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dc.type.version","published_version"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.artnumber","6008"],["dc.bibliographiccitation.firstpage","1"],["dc.bibliographiccitation.journal","Nature Communications"],["dc.bibliographiccitation.lastpage","11"],["dc.bibliographiccitation.volume","6"],["dc.contributor.author","Xu, Xingbo"],["dc.contributor.author","Smorag, Lukasz"],["dc.contributor.author","Nakamura, Toshinobu"],["dc.contributor.author","Kimura, Tohru"],["dc.contributor.author","Dressel, Ralf"],["dc.contributor.author","Fitzner, Antje"],["dc.contributor.author","Tan, Xiaoying"],["dc.contributor.author","Linke, Matthias"],["dc.contributor.author","Zechner, Ulrich"],["dc.contributor.author","Engel, Wolfgang"],["dc.contributor.author","Pantakani, D.V. Krishna"],["dc.date.accessioned","2018-11-07T10:03:46Z"],["dc.date.available","2018-11-07T10:03:46Z"],["dc.date.issued","2015"],["dc.description.abstract","Reprogramming of mouse somatic cells into induced pluripotent stem cells (iPSCs) often generates partially reprogrammed iPSCs (pre-iPSCs), low-grade chimera forming iPSCs (lg-iPSCs) and fully reprogrammed, high-grade chimera production competent iPSCs (hg-iPSCs). Lg-iPSC transcriptome analysis revealed misregulated Dlk1-Dio3 cluster gene expression and subsequently the imprinting defect at the Dlk1-Dio3 locus. Here, we show that germ-cell marker Dppa3 is present only in lg-iPSCs and hg-iPSCs, and that induction with exogenous Dppa3 enhances reprogramming kinetics, generating all hg-iPSCs, similar to vitamin C (Vc). Conversely, Dppa3-null fibroblasts show reprogramming block at pre-iPSCs state and Dlk1-Dio3 imprinting defect. At the molecular level, we show that Dppa3 is associated with Dlk1-Dio3 locus and identify that Dppa3 maintains imprinting by antagonizing Dnmt3a binding. Our results further show molecular parallels between Dppa3 and Vc in Dlk1-Dio3 imprinting maintenance and suggest that early activation of Dppa3 is one of the cascades through which Vc facilitates the generation of fully reprogrammed iPSCs."],["dc.identifier.doi","10.1038/ncomms7008"],["dc.identifier.isi","000348812400009"],["dc.identifier.pmid","25613421"],["dc.identifier.purl","https://resolver.sub.uni-goettingen.de/purl?gs-1/11863"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/38545"],["dc.identifier.url","https://sfb1002.med.uni-goettingen.de/production/literature/publications/130"],["dc.language.iso","en"],["dc.notes.intern","Merged from goescholar"],["dc.notes.status","final"],["dc.notes.submitter","Najko"],["dc.relation","SFB 1002: Modulatorische Einheiten bei Herzinsuffizienz"],["dc.relation","SFB 1002 | C05: Bedeutung von zellulären Immunreaktionen für das kardiale Remodeling und die Therapie der Herzinsuffizienz durch Stammzelltransplantation"],["dc.relation.issn","2041-1723"],["dc.relation.workinggroup","RG Dressel"],["dc.rights","CC BY 4.0"],["dc.rights.uri","https://creativecommons.org/licenses/by/4.0"],["dc.title","Dppa3 expression is critical for generation of fully reprogrammed iPS cells and maintenance of Dlk1-Dio3 imprinting"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.subtype","original_ja"],["dc.type.version","published_version"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","61"],["dc.bibliographiccitation.issue","1"],["dc.bibliographiccitation.journal","Stem Cell Research"],["dc.bibliographiccitation.lastpage","74"],["dc.bibliographiccitation.volume","13"],["dc.contributor.author","Nyamsuren, Gunsmaa"],["dc.contributor.author","Kata, Aleksandra"],["dc.contributor.author","Xu, X."],["dc.contributor.author","Raju, Priyadharsini"],["dc.contributor.author","Dressel, Ralf"],["dc.contributor.author","Engel, Wolfgang"],["dc.contributor.author","Pantakani, Dasaradha Venkata Krishna"],["dc.contributor.author","Adham, Ibrahim M."],["dc.date.accessioned","2018-11-07T09:37:55Z"],["dc.date.available","2018-11-07T09:37:55Z"],["dc.date.issued","2014"],["dc.description.abstract","Pelota (Pelo) is ubiquitously expressed, and its genetic deletion in mice leads to embryonic lethality at an early post-implantation stage. In the present study, we conditionally deleted Pelo and showed that PELO deficiency did not markedly affect the self-renewal of embryonic stem cells (ESCs) or their capacity to differentiate in teratoma assays. However, their differentiation into extraembryonic endoderm (ExEn) in embryoid bodies (EBs) was severely compromised. Conversely, forced expression of Pelo in ESCs resulted in spontaneous differentiation toward the ExEn lineage. Failure of Pelo-deficient ESCs to differentiate into ExEn was accompanied by the retained expression of pluripotency-related genes and alterations in expression of components of the bone morphogenetic protein (BMP) signaling pathway. Further experiments have also revealed that attenuated activity of BMP signaling is responsible for the impaired development of ExEn. The recovery of ExEn and down-regulation of pluripotent genes in BMP4-treated Pelo-null EBs indicate that the failure of mutant cells to down-regulate pluripotency-related genes in EBs is not a result of autonomous defect, but rather to failed signals from surrounding ExEn lineage that induce the differentiation program. In vivo studies showed the presence of ExEn in Pelo-null embryos at E6.5, yet embryonic lethality at E7.5, suggesting that PELO is not required for the induction of ExEn development, but rather for ExEn maintenance or for terminal differentiation toward functional visceral endoderm which provides the embryos with growth factors required for further development. Moreover, Pelo-null fibroblasts failed to reprogram toward induced pluripotent stem cells (iPSCs) due to inactivation of BMP signaling and impaired mesenchymal-to-epithelial transition. Thus, our results indicate that PELO plays an important role in the establishment of pluripotency and differentiation of ESCs into ExEn lineage through activation of BMP signaling. (C) 2014 The Authors. Published by Elsevier B.V."],["dc.description.sponsorship","Open-Access-Publikationsfonds 2014"],["dc.identifier.doi","10.1016/j.scr.2014.04.011"],["dc.identifier.isi","000342287000006"],["dc.identifier.pmid","24835669"],["dc.identifier.purl","https://resolver.sub.uni-goettingen.de/purl?gs-1/10452"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/32951"],["dc.notes.intern","Merged from goescholar"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Elsevier Science Bv"],["dc.relation.issn","1876-7753"],["dc.relation.issn","1873-5061"],["dc.rights","CC BY 3.0"],["dc.rights.uri","https://creativecommons.org/licenses/by/3.0"],["dc.title","Pelota regulates the development of extraembryonic endoderm through activation of bone morphogenetic protein (BMP) signaling"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dc.type.version","published_version"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","677"],["dc.bibliographiccitation.issue","11"],["dc.bibliographiccitation.journal","Biology of the Cell"],["dc.bibliographiccitation.lastpage","692"],["dc.bibliographiccitation.volume","104"],["dc.contributor.author","Smorag, Lukasz"],["dc.contributor.author","Zheng, Y."],["dc.contributor.author","Nolte, Jessica"],["dc.contributor.author","Zechner, Ulrich"],["dc.contributor.author","Engel, Wolfgang"],["dc.contributor.author","Pantakani, Dasaradha Venkata Krishna"],["dc.date.accessioned","2018-11-07T09:04:07Z"],["dc.date.available","2018-11-07T09:04:07Z"],["dc.date.issued","2012"],["dc.description.abstract","Background information Recently, it became apparent that microRNAs (miRNAs) can regulate gene expression post-transcriptionally. Despite the advances in identifying the testis-expressed miRNAs and their role in spermatogenesis, only few data are available showing the spatiotemporal expression of miRNAs during this process. Results To understand how different miRNAs can regulate germ cells differentiation, we generated a transgenic mouse model and purified pure populations of premeiotic (PrM) cells and primary spermatocytes (meiotic cells). We also established spermatogonial stem cell (SSC) culture using relatively simple and robust culture conditions. Comparison of global miRNA expression in these germ cell populations revealed 17 SSC-, 11 PrM- and 13 meiotic-specific miRNAs. We identified nine miRNAs as specific for both SSC and PrM cells and another nine miRNAs as specific for PrM and meiotic cells. Additionally, 45 miRNAs were identified as commonly expressed in all three cell types. Several of PrM- and meiotic-specific miRNAs were identified as exclusively/preferentially expressed in testis. We were able to identify the relevant target genes for many of these miRNAs. The luciferase reporter assays with SSC (miR-221)-, PrM (miR-203)- and meiotic (miR-34b-5p)-specific miRNAs and 3'-untranslated region constructs of their targets, c-Kit, Rbm44 and Cdk6, respectively, showed an approximately 30%40% decrease in reporter activity. Moreover, we observed a reduced expression of endogenous proteins, c-Kit and Cdk6, when the testis-derived cell lines, GC-1 and GC-4, were transfected with miRNA mimics for miR-221 and miR-34b-5p, respectively. Conclusions Taken together, we established the miRNA signature of SSC, PrM and meiotic cells and show evidence for their functional relevance during the process of spermatogenesis by target prediction and validation. Through our observations, we propose a working model in which the stage-specific miRNAs such as miR-221, -203 and -34b-5p coordinate the regulation of spermatogenesis."],["dc.identifier.doi","10.1111/boc.201200014"],["dc.identifier.isi","000310391100006"],["dc.identifier.pmid","22909339"],["dc.identifier.purl","https://resolver.sub.uni-goettingen.de/purl?gs-1/9536"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/25040"],["dc.notes.intern","Merged from goescholar"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Wiley-blackwell"],["dc.relation.issn","1768-322X"],["dc.relation.issn","0248-4900"],["dc.rights","Goescholar"],["dc.rights.uri","https://goescholar.uni-goettingen.de/licenses"],["dc.title","MicroRNA signature in various cell types of mouse spermatogenesis: Evidence for stage-specifically expressed miRNA-221, -203 and -34b-5p mediated spermatogenesis regulation"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dc.type.version","published_version"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","228"],["dc.bibliographiccitation.issue","2"],["dc.bibliographiccitation.journal","Molecular Biotechnology"],["dc.bibliographiccitation.lastpage","237"],["dc.bibliographiccitation.volume","54"],["dc.contributor.author","Zheng, Y."],["dc.contributor.author","Tan, Xiaoying"],["dc.contributor.author","Pyczek, Joanna"],["dc.contributor.author","Nolte, Jessica"],["dc.contributor.author","Pantakani, Dasaradha Venkata Krishna"],["dc.contributor.author","Engel, Wolfgang"],["dc.date.accessioned","2018-11-07T09:24:28Z"],["dc.date.available","2018-11-07T09:24:28Z"],["dc.date.issued","2013"],["dc.description.abstract","Pluripotent stem cells have the therapeutic potential in future regenerative medicine applications. Therefore, it is highly important to understand the molecular mechanisms governing the pluripotency and differentiation potential of these cells. Our current knowledge of pluripotent cells is largely limited owing to the candidate gene/protein approach rather than studying the complex interactions of the proteins. Experimentally, yeast two-hybrid system (Y2H) is by far the most useful and widely used method to detect the protein-protein interactions in high-throughput screenings. Unfortunately, currently there is no GAL4-based pluripotent stem cell-specific cDNA library available for screening the interaction proteins impeding the large-scale studies. In this study, we report the construction of Y2H cDNA libraries derived from mouse pluripotent embryonic stem cells (ESCs) and multipotent adult germ-line stem cells (maGSCs) in GAL4-based Y2H vector system with very high transformation efficiency. Furthermore, we have constructed two different baits and screened for interaction partners in an effort to characterize the libraries and also as a part of our ongoing studies. Consequently, many putative interaction proteins were identified in both cases and their interaction was further validated by direct-Y2H. The observed interactions between bait proteins and their respective analyzed putative interaction proteins were further confirmed using two independent approaches in mammalian cells, thus highlighting the biological significance of the identified interactor (s). Finally, we would like to make these cDNA libraries as a resource that can be distributed to the research community."],["dc.identifier.doi","10.1007/s12033-012-9561-4"],["dc.identifier.isi","000318308400013"],["dc.identifier.pmid","22674187"],["dc.identifier.purl","https://resolver.sub.uni-goettingen.de/purl?gs-1/10389"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/29830"],["dc.notes.intern","Merged from goescholar"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Humana Press Inc"],["dc.relation.issn","1073-6085"],["dc.rights","Goescholar"],["dc.rights.uri","https://goescholar.uni-goettingen.de/licenses"],["dc.title","Generation and Characterization of Yeast Two-Hybrid cDNA Libraries Derived From Two Distinct Mouse Pluripotent Cell Types"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dc.type.version","published_version"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.artnumber","e48869"],["dc.bibliographiccitation.issue","11"],["dc.bibliographiccitation.journal","PLoS ONE"],["dc.bibliographiccitation.volume","7"],["dc.contributor.author","Khromov, Tatjana"],["dc.contributor.author","Dressel, Ralf"],["dc.contributor.author","Siamishi, Iliana"],["dc.contributor.author","Nolte, Jessica"],["dc.contributor.author","Opitz, Lennart"],["dc.contributor.author","Engel, Wolfgang"],["dc.contributor.author","Pantakani, Dasaradha Venkata Krishna"],["dc.date.accessioned","2018-11-07T09:03:34Z"],["dc.date.available","2018-11-07T09:03:34Z"],["dc.date.issued","2012"],["dc.description.abstract","Stem cells in the developing embryo proliferate and differentiate while maintaining genomic integrity, failure of which may lead to accumulation of mutations and subsequent damage to the embryo. Embryonic stem cells (ESCs), the in vitro counterpart of embryo stem cells are highly sensitive to genotoxic stress. Defective ESCs undergo either efficient DNA damage repair or apoptosis, thus maintaining genomic integrity. However, the genotoxicity- and apoptosis-related processes in germ-line derived pluripotent cells, multipotent adult germ-line stem cells (maGSCs), are currently unknown. Here, we analyzed the expression of apoptosis-related genes using OligoGEArray in undifferentiated maGSCs and ESCs and identified a similar set of genes expressed in both cell types. We detected the expression of intrinsic, but not extrinsic, apoptotic pathway genes in both cell types. Further, we found that apoptosis-related gene expression patterns of differentiated ESCs and maGSCs are identical to each other. Comparative analysis revealed that several pro-and antiapoptotic genes are expressed specifically in pluripotent cells, but markedly downregulated in the differentiated counterparts of these cells. Activation of the intrinsic apoptotic pathway cause approximately similar to 35% of both ESCs and maGSCs to adopt an early-apoptotic phenotype. Moreover, we performed transcriptome studies using early-apoptotic cells to identify novel pluripotency- and apoptosis-related genes. From these transcriptome studies, we selected Fgf4 (Fibroblast growth factor 4) and Mnda (Myeloid cell nuclear differentiating antigen), which are highly downregulated in early-apoptotic cells, as novel candidates and analyzed their roles in apoptosis and genotoxicity responses in ESCs. Collectively, our results show the existence of common molecular mechanisms for maintaining the pristine stem cell pool of both ESCs and maGSCs."],["dc.description.sponsorship","Open-Access-Publikationsfonds 2012"],["dc.identifier.doi","10.1371/journal.pone.0048869"],["dc.identifier.isi","000311935800158"],["dc.identifier.pmid","23145002"],["dc.identifier.purl","https://resolver.sub.uni-goettingen.de/purl?gs-1/8319"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/24921"],["dc.notes.intern","Merged from goescholar"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Public Library Science"],["dc.relation.issn","1932-6203"],["dc.rights","CC BY 2.5"],["dc.rights.uri","https://creativecommons.org/licenses/by/2.5"],["dc.title","Apoptosis-Related Gene Expression Profiles of Mouse ESCs and maGSCs: Role of Fgf4 and Mnda in Pluripotent Cell Responses to Genotoxicity"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dc.type.version","published_version"],["dspace.entity.type","Publication"]]