The DP-1 Transcription Factor Is Required for Keratinocyte Growth and Epidermal Stratification

Chang, Wing Y.; Bryce, Dawn M.; D’Souza, Sudhir J.A.; Dagnino, Lina

doi:10.1074/jbc.m408635200

Cited by 26 publications

(19 citation statements)

References 71 publications

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“…Comparison of p110 CUX1 and E2F1 targets indicated that 86 targets were common to E2F1 and p110 (see Table S2 in the supplemental material). To this list, we added 22 genes that were identified as E2F targets in previous studies (5,8,18,46,57,81,85,87) (see Table S2 in the supplemental material). Of the common targets, 20% were genes involved in cell cycle progression, DNA replication, or DNA repair (see Table S3 in the supplemental material).…”

Section: Resultsmentioning

confidence: 99%

p110 CUX1 Cooperates with E2F Transcription Factors in the Transcriptional Activation of Cell Cycle-Regulated Genes

Truscott

Harada

Vadnais

et al. 2008

Molecular and Cellular Biology

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The transcription factor p110 CUX1 was shown to stimulate cell proliferation by accelerating entry into S phase. As p110 CUX1 can function as a transcriptional repressor or activator depending on promoter context, we investigated its mechanism of transcriptional activation using the DNA polymerase ␣ gene promoter as a model system. Linker-scanning analysis revealed that a low-affinity E2F binding site is required for transcriptional activation. Moreover, coexpression with a dominant-negative mutant of DP-1 suggested that endogenous E2F factors are indeed needed for p110-mediated activation. Tandem affinity purification, coimmunoprecipitation, chromatin immunoprecipitation, and reporter assays indicated that p110 CUX1 can engage in weak protein-protein interactions with E2F1 and E2F2, stimulate their recruitment to the DNA polymerase ␣ gene promoter, and cooperate with these factors in transcriptional activation. On the other hand, in vitro assays suggested that the interaction between CUX1 and E2F1 either is not direct or is regulated by posttranslational modifications. Genome-wide location analysis revealed that targets common to p110 CUX1 and E2F1 included many genes involved in cell cycle, DNA replication, and DNA repair. Comparison of the degree of enrichment for various E2F factors suggested that binding of p110 CUX1 to a promoter will favor the specific recruitment of E2F1, and to a lesser extent E2F2, over E2F3 and E2F4. Reporter assays on a subset of common targets confirmed that p110 CUX1 and E2F1 cooperate in their transcriptional activation. Overall, our results show that p110 CUX1 and E2F1 cooperate in the regulation of many cell cycle genes.CUX1 (cut homeobox) belongs to a family of transcription factors involved in the control of proliferation and differentiation (reviewed in reference 52). Several CUX1 isoforms can be expressed as a result of proteolytic processing or transcription initiation at alternative sites (21,23,45,49,70). Cux1 gene ablation in mice resulted in high perinatal lethality. Surviving mice exhibited a number of mutant phenotypes, including growth retardation, male infertility, curly whiskers, abnormal hair follicle morphogenesis, and a shortage of T and B cells (13,43,63,73). Transgenic mice expressing p200 CUX1 exhibited multiorgan hyperplasia and organomegaly (36), whereas those expressing p75 or p110 CUX1 displayed enhanced susceptibility to malignancies in various tissues and cell types (4; C. Cadieux and A. Nepveu, unpublished data).Initial studies of mammalian CUX1 revealed its role as a transcriptional repressor that is expressed in differentiating precursor cells and serves to down-regulate the expression of genes expressed only in terminally differentiated cells (41,55,64,66,67). CUX1 was also reported to regulate the expression of cell cycle-regulated genes such as those encoding p21 WAF1 (7), histones H1, H2A, H2B, H3, and H4 (12, 27, 74, 76), and DNA polymerase (Pol) ␣ (71). The full-length protein, p200 CUX1, interacts transiently with DNA and is expressed througho...

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Section: Resultsmentioning

confidence: 99%

p110 CUX1 Cooperates with E2F Transcription Factors in the Transcriptional Activation of Cell Cycle-Regulated Genes

Truscott

Harada

Vadnais

et al. 2008

Molecular and Cellular Biology

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“…During epidermal development and keratinocyte differentiation, E2F forms are modulated at multiple levels, including mRNA and protein abundance, interactions with pRb family proteins and subcellular distribution (D'Souza et al, 2001;Apostolova et al, 2002). E2F activity is essential for proper epidermal morphogenesis and keratinocyte proliferation, as evidenced by the perturbations in these processes caused by exogenous expression of a dn DP-1 mutant in primary cultured keratinocytes and embryonic ectodermal explants (Chang et al, 2004). Further, E2F1 fulfills essential, nonredundant functions in epidermal keratinocytes.…”

Section: Discussionmentioning

confidence: 99%

E2F1 stability is regulated by a novel-PKC/p38β MAP kinase signaling pathway during keratinocyte differentiation

2005

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E2F transcription factors regulate proliferation, differentiation, DNA repair and apoptosis. Tight E2F regulation is crucial for epidermal formation and regeneration. However, virtually nothing is known about the molecular events modulating E2F during epidermal keratinocyte differentiation. Elucidation of these events is essential to understand epidermal morphogenesis, transformation and repair. Here we show that, in differentiating keratinocytes, Ca 2 þ -induced protein kinase C (PKC) activation downregulates E2F1 protein levels. Further, we have identified PKC d and g as those isoforms specifically involved in induction of E2F1 proteasomal degradation. We also demonstrate that E2F1 downregulation by novel PKC isozymes requires activation of p38b mitogenactivated protein kinase (MAPK). This is the first example of regulation in the E2F transcription factor family by activation of PKC and MAPK in the context of biologically significant differentiation stimuli in epithelia.

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“…E2F DNA binding is known to be associated with keratinocyte proliferation (31). Chromatin immunoprecipitation analysis demonstrated that the cyclin A promoter is predominantly bound in proliferating keratinocytes by complexes containing E2F3 and that E2F3 is implicated in epidermal formation (32). E2F3, a known target of miR-210 (17), emerges as an important mediator of hypoxia-induced impairment of re-epithelialization of the ischemic wound.…”

Section: Discussionmentioning

confidence: 99%

Hypoxia inducible microRNA 210 attenuates keratinocyte proliferation and impairs closure in a murine model of ischemic wounds

Biswas¹,

Roy²,

Banerjee³

et al. 2010

Proc. Natl. Acad. Sci. U.S.A.

250

199

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Ischemia complicates wound closure. Here, we are unique in presenting a murine ischemic wound model that is based on bipedicle flap approach. Using this model of ischemic wounds we have sought to elucidate how microRNAs may be implicated in limiting wound reepithelialization under hypoxia, a major component of ischemia. Ischemia, evaluated by laser Doppler as well as hyperspectral imaging, limited blood flow and lowered tissue oxygen saturation. EPR oximetry demonstrated that the ischemic wound tissue had pO 2 <10 mm Hg. Ischemic wounds suffered from compromised macrophage recruitment and delayed wound epithelialization. Specifically, epithelial proliferation, as determined by Ki67 staining, was compromised. In vivo imaging showed massive hypoxia inducible factor-1α (HIF-1α) stabilization in ischemic wounds, where HIF-1α induced miR-210 expression that, in turn, silenced its target E2F3, which was markedly down-regulated in the wound-edge tissue of ischemic wounds. E2F3 was recognized as a key facilitator of cell proliferation. In keratinocytes, knock-down of E2F3 limited cell proliferation. Forced stabilization of HIF-1α using Ad-VP16-HIF-1α under normoxic conditions upregulated miR-210 expression, down-regulated E2F3, and limited cell proliferation. Studies using cellular delivery of miR-210 antagomir and mimic demonstrated a key role of miR-210 in limiting keratinocyte proliferation. In summary, these results are unique in presenting evidence demonstrating that the hypoxia component of ischemia may limit wound re-epithelialization by stabilizing HIF-1α, which induces miR-210 expression, resulting in the down-regulation of the cell-cycle regulatory protein E2F3.skin | tissue repair | wound healing

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The DP-1 Transcription Factor Is Required for Keratinocyte Growth and Epidermal Stratification

Cited by 26 publications

References 71 publications

p110 CUX1 Cooperates with E2F Transcription Factors in the Transcriptional Activation of Cell Cycle-Regulated Genes

p110 CUX1 Cooperates with E2F Transcription Factors in the Transcriptional Activation of Cell Cycle-Regulated Genes

E2F1 stability is regulated by a novel-PKC/p38β MAP kinase signaling pathway during keratinocyte differentiation

Hypoxia inducible microRNA 210 attenuates keratinocyte proliferation and impairs closure in a murine model of ischemic wounds

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