Octamer-binding transcription factors: genomics and functions

Zhao, Feng‐Qi

doi:10.2741/4162

Cited by 56 publications

(76 citation statements)

References 191 publications

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“…3), which is specific for mammalian stem cells and features homology to pluripotency factors and target genes between neoblast trascriptomes and proteomes (13). These results are consistent with those of others studies (13,17), demonstrating that OCT4 is a good neoblast label, independent of the use of a planarian species as a model, as this gene evolutionarily conserved pluripotency.…”

Section: A B a B Csupporting

confidence: 88%

Section: Introductionmentioning

confidence: 99%

“…Pluripotency transcription factors in mammalian stem cells are regulated by key genes, such as OCT4, SOX2 and NANOG. OCT4 is a member of the octamer-binding subgroup of the Pit-Oct-Unc transcription factor family (16,17).Due to a lack of information on the establishment of planarian primary neoblast cultures, particularly of Girardia tigrina, the present study proposed a methodology for cell culture establishment and characterization of neoblasts. …”

mentioning

confidence: 99%

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Method of isolation and characterization of Girardia tigrina stem cells

2014

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Abstract. Tissue regeneration is widely studied due to its importance for understanding the biology of stem cells, aiming at their application in medicine for therapeutic and various other purposes. The establishment of experimental models is necessary, as certain invertebrates and vertebrates have different regeneration abilities depending on their taxon position on the evolutionary scale. Planarians are an efficacious in vivo model for stem cell biology, but the correlation between planarian cellular and molecular neoblast pluripotency mechanisms and those of mammalian stem cells is unknown. The present study had the following objectives: i) Establish Girardia tigrina cell culture, ii) determine the time required for complete cell disintegration and iii) obtain neoblasts by cell subdivision. Twenty-four specimens were deprived of food for seven days. After this time, disintegration was performed by incubation protected at three temperatures for 48 h in an antibiotic, antimycotic and trypsin solution, after which the suspension was homogenized and centrifuged. Histopaque ® 1077 was used for cell separation and interphases were collected and monitored by optical and fluorescence microscopy. Optical microscopy analysis informed the nucleus-to-cytoplasm ratio, cell morphology and cell size. Under fluorescence microscopy, interphase 1 (I1) was subdivided into two groups and neoblasts were marked for characterization; one group was stained with 4',6-diamidino-2-phenylindole and the other was immunolabeled with octamer-binding transcription factor 4 (OCT4) and isolated and observed after 10 days of cultivation. Neoblasts predominated in I1 with a small amount of other cell types. In conclusion, sample disintegration with a trypsin and antibiotic solution was effective at 18˚C and Iscove's modified Dulbecco's medium supplemented with fetal bovine serum was adequate for the establishment of primary cell cultures after 48-h incubation and centrifugation. Antibody anti-OCT4 was used for the characterization of stem cells and was successfully labeled with concentrated neoblasts on interphase 1. IntroductionRegeneration is a complex event that occurs in several vertebrates and invertebrates (1). For regeneration to occur, one of the earliest signaling events following a lesion is the production of cells that are capable of rebuilding lost structures. The way that these events occur and the types of cells involved differ between animal groups (2).The choice of planarians as a regeneration study model is based on their plasticity, regeneration ability, rapid response and adult stem cell reservoir (3). Cell and molecular characterization of planarian stem cells has been achieved with various tools, such as inhibition of the function of genes involved in regeneration via RNA interference, western blotting, in situ hybridization and cell isolation by flow cytometry (4-8). These tools are extremely important alternatives for understanding the mechanisms associated with the maintenance and role of stem cells in vivo (9).Stem cell...

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Section: A B a B Csupporting

confidence: 88%

Section: Introductionmentioning

confidence: 99%

mentioning

confidence: 99%

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Method of isolation and characterization of Girardia tigrina stem cells

2014

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“…Oct-1 (gene symbol POU2F1 ) is a member of the POU domain DNA-binding transcription regulators of higher eukaryotes (1–4). The Oct-1 POU domain interacts as a monomer with an octamer motif ATGCAAAT (2) and related sequences (5–9).…”

Section: Introductionmentioning

confidence: 99%

Different N-terminal isoforms of Oct-1 control expression of distinct sets of genes and their high levels in Namalwa Burkitt's lymphoma cells affect a wide range of cellular processes

et al. 2016

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Oct-1 transcription factor has various functions in gene regulation. Its expression level is increased in several types of cancer and is associated with poor survival prognosis. Here we identified distinct Oct-1 protein isoforms in human cells and compared gene expression patterns and functions for Oct-1A, Oct-1L, and Oct-1X isoforms that differ by their N-terminal sequences. The longest isoform, Oct-1A, is abundantly expressed and is the main Oct-1 isoform in most of human tissues. The Oct-1L and the weakly expressed Oct-1X regulate the majority of Oct-1A targets as well as additional sets of genes. Oct-1X controls genes involved in DNA replication, DNA repair, RNA processing, and cellular response to stress. The high level of Oct-1 isoforms upregulates genes related to cell cycle progression and activates proliferation both in Namalwa Burkitt's lymphoma cells and primary human fibroblasts. It downregulates expression of genes related to antigen processing and presentation, cytokine-cytokine receptor interaction, oxidative metabolism, and cell adhesion, thus facilitating pro-oncogenic processes.

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“…We report herein the identification of a new mechanism of regulation of the HMGA1 gene, which involves the octamer DNA motif “ATGCAAAT” originally described in immunoglobulin ( Ig ) gene regulation [23]. As a cis -acting transcriptional regulatory element found in both promoters and enhancers of a wide variety of ubiquitously expressed and cell type-specific genes, this octamer motif is specifically bound by a family of at least 11 distinct nuclear proteins, named octamer-binding (Oct) transcription factors, designated from Oct-1 to Oct-11 [24]. All these factors are characterized by two Pit-Oct-Unc (POU) domains, in which the N-terminal subunit is known as the POU-specific (POUS) domain, while the C-terminal subunit is a homeo domain (POUH).…”

Section: Introductionmentioning

confidence: 99%

Transcriptional Regulation of the HMGA1 Gene by Octamer-Binding Proteins Oct-1 and Oct-2

et al. 2013

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The High-Mobility Group AT-Hook 1 (HMGA1) protein is an architectural transcription factor that binds to AT-rich sequences in the promoter region of DNA and functions as a specific cofactor for gene activation. Previously, we demonstrated that HMGA1 is a key regulator of the insulin receptor (INSR) gene and an important downstream target of the INSR signaling cascade. Moreover, from a pathogenic point of view, overexpression of HMGA1 has been associated with human cancer, whereas functional variants of the HMGA1 gene have been recently linked to type 2 diabetes mellitus and metabolic syndrome. However, despite of this biological and pathological relevance, the mechanisms that control HMGA1 gene expression remain unknown. In this study, to define the molecular mechanism(s) that regulate HMGA1 gene expression, the HMGA1 gene promoter was investigated by transient transfection of different cell lines, either before or after DNA and siRNA cotransfections. An octamer motif was identified as an important element of transcriptional regulation of this gene, the interaction of which with the octamer transcription factors Oct-1 and Oct-2 is crucial in modulating HMGA1 gene and protein expression. Additionally, we demonstrate that HMGA1 binds its own promoter and contributes to its transactivation by Oct-2 (but not Oct-1), supporting its role in an auto-regulatory circuit. Overall, our results provide insight into the transcriptional regulation of the HMGA1 gene, revealing a differential control exerted by both Oct-1 and Oct-2. Furthermore, they consistently support the hypothesis that a putative defect in Oct-1 and/or Oct-2, by affecting HMGA1 expression, may cause INSR dysfunction, leading to defects of the INSR signaling pathway.

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Octamer-binding transcription factors: genomics and functions

Cited by 56 publications

References 191 publications

Method of isolation and characterization of Girardia tigrina stem cells

Method of isolation and characterization of Girardia tigrina stem cells

Different N-terminal isoforms of Oct-1 control expression of distinct sets of genes and their high levels in Namalwa Burkitt's lymphoma cells affect a wide range of cellular processes

Transcriptional Regulation of the HMGA1 Gene by Octamer-Binding Proteins Oct-1 and Oct-2

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