Breast-conserving in centrally located breast cancer patients confirmed safe by SEER based study.

BACKGROUND: Due to the lack of high-level data, there is still controversy over the oncological safety of breast conservation in patients with centrally located breast cancer. This study aimed to assess the safety of breast-conserving surgery in patients with centrally located breast cancer based on the data from the Surveillance, Epidemiology, and End Results (SEER) database. METHODS: We collected data for all cases diagnosed with breast cancer who underwent breast-conserving surgery from 2012-2014 in the SEER database. The primary outcome of our study was disease-specific survival (DSS) and overall survival (OS). The PSM was used to eliminate the effects of non-random statistics. Chi-square test, Kaplan-Meier method and Cox proportional hazards regression model on univariate and multivariate analysis were used to analyze the data. RESULTS: Data from 79,214 patients who had undergone breast-conserving surgery were analyzed in this study, including those with breast cancer in the central region (n=3,128) and outside the central region (n=76,086). The DSS of central breast cancer patients and outside the central breast cancer patients was 58.1 months versus 58.0 months (P>0.05), respectively, while the OS of the 2 groups was 58.0 months versus 58.0 months (P>0.05), respectively. CONCLUSIONS: Breast cancer in the central region should not be contraindicated for breast conserving surgery and breast-conserving surgery can benefit a wider range of patients.

miR-30b protects nigrostriatal dopaminergic neurons from MPP(+)-induced neurotoxicity via SNCA.

OBJECTIVE: To explore the function of miR-30b in pathogenesis of Parkinson's disease (PD) and its underlying molecular mechanism. MATERIALS AND METHODS: We used 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPP(+)) as a tool for constructing the PD cell model, using miR-30b mimics or inhibitors to manipulate miR-30b level for an experimental model of acquisition. The cell viability of SH-SY5Y was detected by CCK, and luciferase was used to screen the binding of target genes. The protein levels of SNCA were measured by Western blot. Then, we investigate the changes in pro- and anti-apoptotic markers with or without miR-30b treatment. RESULTS: There was a significant low expression of MiR-30b in MPP(+)-induced cells. SH-SY5Y cell viability was rescued by MiR-30b overexpression. Luciferase experiments showed that MiR-30b may bind to the 3'-UTR side of SNCA and inhibited its expression. By Western blot, the SNCA level was markedly decreased by miR-30b. miR-30b attenuated the upregulation of Bax and the depletion of Bcl-2 induced by MPP(+).

Evaluation of Clinical Outcome and Risk Factors for Recurrence after Pelvic Reconstruction of Pelvic Organ Prolapse with Implanted Mesh or Biological Grafts: A Single-Blind Randomized Trial.

BACKGROUND: There are few studies on the relative factors related to postoperative recurrence. OBJECTIVES: To compare the outcomes of pelvic floor reconstruction involving Herniamesh mesh and biological grafts and to investigate the correlative factors of postoperative recurrence. METHOD: Two hundred and thirty-two patients were randomly divided into 2 groups: Herniamesh mesh group (117) and biological graft group (115). Follow-ups for 6 months and 1 year after the surgery. The primary outcomes were recurrence, perioperative complications. Secondary outcome was a questionnaire about the life habits associated with relapse. RESULTS: The recurrence rate at 6 months or 1 year did not differ substantially between the 2 groups (p = 0.787 and 0.968, respectively). Adverse events occurred with significantly different frequencies over 1 year (p = 0.005). Twelve factors were investigated and analyzed by logistic regression analysis. It showed that recurrence had a strong association with a long-term vegetarian diet (OR 0.283, 95% CI 0.117-0.683), long-term soybean product diet (OR 8.010, 95% CI 2.514-25.523), and vaginal intercourse (OR 5.154, 95% CI 1.461-18.184). CONCLUSIONS: The surgical recurrence rate for the mesh was similar to biological grafts at short-term follow-up. Eating soy products often and vaginal intercourse after surgery can reduce recurrence.

PCAF-mediated acetylation of Lin28B increases let-7 biogenesis in lung adenocarcinoma H1299 cells.

BACKGROUND: Lin28B and its paralog Lin28A are small RNA binding proteins that have similar inhibitory effects, although they target separate steps in the maturation of let-7 miRNAs in mammalian cells. Because Lin28B participates in the promotion and development of tumors mostly by blocking the let-7 tumor suppressor family members, we sought to explore the associated mechanisms to gain insights into how Lin28B might be decreased in human cancer cells to increase let-7 levels and reverse malignancy. RESULTS: We demonstrated that the histone acetyltransferase PCAF, via its cold shock domain, directly interacts with and subsequently acetylates Lin28B in lung adenocarcinoma-derived H1299 cells. RT-qPCR assays showed that both let-7a-1 and let-7g were increased in PCAF-transfected H1299 cells. Lin28B is acetylated by ectopic PCAF and translocates from the nucleus to the cytoplasm in H1299 cells. CONCLUSIONS: The effects of acetylated Lin28B on let-7a-1 and let-7g are similar to that of stable knockdown of Lin28B in H1299 cells. The new role of PCAF in mediating Lin28B acetylation and the specific release of its target microRNAs in H1299 cells may shed light on the potential application of let-7 in the clinical treatment of lung cancer patients.

CRIF1 enhances p53 activity via the chromatin remodeler SNF5 in the HCT116 colon cancer cell lines.

CR6-interacting factor 1 (CRIF1) is ubiquitously expressed in human tissues. CRIF1 was first identified as a Gadd45γ (also known as CR6)-interacting protein, and it was also identified in a human colon cancer cell line stably transformed with p53. These results suggested that CRIF1 functions in the nucleus with p53 and Gadd45 family proteins in the suppression of cell growth and tumor development. Here, we found that CRIF1 could be recruited to a specific region in the promoter of the p53 gene, eliciting an increase in the mRNA and protein levels of p53 as well as p53 functional target genes. These functions required CRIF1 to interact with SNF5. CRIF1 was further recruited to the upstream promoter region of the p53 gene to suppress cell cycle progression in HCT116 cells. To our knowledge, this is the first evidence indicating that SNF5 is indispensable for CRIF1-enhanced p53 activity and its function in the suppression of cell cycle arrest in human cancer cells.

Histone deacetylase 4 increases progressive epithelial ovarian cancer cells via repression of p21 on fibrillar collagen matrices.

Histone deacetylase (HDAC) 4 is an emerging target in cancer therapeutics, but little is known about the function of HDAC4 in gynecologic malignancies. Therefore we investigated the mechanism of HDAC4 promoting the proliferation of epithelial ovarian cancer cells (OV). In this study, we observed that the proliferation of cells with HDAC4 inhibitor Trichostatin A (TSA) treatment was markedly decreased, Further, we showed that epithelial ovarian cancer tissues with stage III/IV had higher HDAC4 expression, compared to that with stage I/II. We examined first that the HDAC4 expression was increased in response to fibrillar collagen matrices. In addition, we found that HDAC4 was retained in the nucleus by regulation of PP1α, which regulated HDAC4 cellular fraction via phosphorylation of HDAC4. In addition, we found that HDAC4 bound to Sp1 in epithelial ovarian cancer cells. Finally, ovarian cancer cell line OVCAR3 was evaluated via gain/loss-of-function of HDAC4 by either overexpression of HDCA4 or knock-down of HDAC4 with shRNA. We examined both protein and mRNA of p21 by western blotting and qPCR. We performed analysis of colony formation in matrigel and migration by ECIS. Our results suggest that the accumulation of HDAC4 induced by fibrillar collagen matrices in the nucleus via co-localization of PP1α, leads to repression of the mRNA/protein of p21 and in turn promotes the proliferation and migration of epithelial ovarian cancer cells.

C/EBPα negatively regulates SIRT7 expression via recruiting HDAC3 to the upstream-promoter of hepatocellular carcinoma cells.

Mammalian Sirtuin proteins (SIRTs) are homologs of yeast Sir2, and characterized as class III histone deacetylases of NAD(+) dependence. Unlike their lower counterparts that are directly involved in the extending of lifespan, mammalian SIRTs mainly function in metabolism and cellular homeostasis, among them, SIRT7 is the least understood. SIRT7 is localized in the nucleus and rich in nucleoli associated with RNA polymerase I, and correlated with cell proliferation. In contrast, SIRT7 has recently been demonstrated to specifically deacetylate H3K18ac in the chromatin, and in most cases represses proliferation. Although MicroRNA as miR-125b has been reported to down-regulate SIRT7 by binding to its 3'UTR, however, how SIRT7 gene is regulated remains unclear. Here, we identified the transcription initiation site of human SIRT7 gene at the upstream 23rd A nucleotide respective to the translational codon, and the SIRT7 is a TATA-less and initiator-less gene. The sequences in the upstream region between -256 and -129 bp are identical with important functions in the three species detected. A C/EBPα responding element is found that binds both C/EBPα and C/EBPß in vitro. We showed TSA induced SIRT7 gene transcription and only the HDAC3, but not its catalytic domain depleted mutant, interacted with C/EBPα to occupy the C/EBPα element and repressed SIRT7 gene in the hepatocellular carcinoma cells. To our knowledge, this is the first report on the regulation mechanism of SIRT7 gene, in which, HDAC3 collaborated with C/EBPα to occupy its responding element in the upstream region of SIRT7 gene and repressed its expression in human cells.

Specific phosphorylation of histone demethylase KDM3A determines target gene expression in response to heat shock.

Histone lysine (K) residues, which are modified by methyl- and acetyl-transferases, diversely regulate RNA synthesis. Unlike the ubiquitously activating effect of histone K acetylation, the effects of histone K methylation vary with the number of methyl groups added and with the position of these groups in the histone tails. Histone K demethylases (KDMs) counteract the activity of methyl-transferases and remove methyl group(s) from specific K residues in histones. KDM3A (also known as JHDM2A or JMJD1A) is an H3K9me2/1 demethylase. KDM3A performs diverse functions via the regulation of its associated genes, which are involved in spermatogenesis, metabolism, and cell differentiation. However, the mechanism by which the activity of KDM3A is regulated is largely unknown. Here, we demonstrated that mitogen- and stress-activated protein kinase 1 (MSK1) specifically phosphorylates KDM3A at Ser264 (p-KDM3A), which is enriched in the regulatory regions of gene loci in the human genome. p-KDM3A directly interacts with and is recruited by the transcription factor Stat1 to activate p-KDM3A target genes under heat shock conditions. The demethylation of H3K9me2 at the Stat1 binding site specifically depends on the co-expression of p-KDM3A in the heat-shocked cells. In contrast to heat shock, IFN-γ treatment does not phosphorylate KDM3A via MSK1, thereby abrogating its downstream effects. To our knowledge, this is the first evidence that a KDM can be modified via phosphorylation to determine its specific binding to target genes in response to thermal stress.

Reversible acetylation of Lin28 mediated by PCAF and SIRT1.

Lin28 is a small RNA-binding protein that plays an important role in regulating developmental timing, stem cell reprogramming, and oncogenesis. However, the significance of the effect of post-translational modifications on Lin28 activity is not fully understood. In this study, we demonstrated that PCAF directly interacted with and acetylated Lin28. We also showed that the acetylation of Lin28 can be specifically reversed by the deacetylase SIRT1. These findings suggest that the PCAF/SIRT1 balance plays an important role in regulating Lin28 activity. Furthermore, we found that the cold shock domain of Lin28 is the major target of PCAF-mediated acetylation, which leads to a severe reduction in the Lin28 protein levels and an increase in the level of mature let-7a. This study provides the first demonstration that post-translational modification regulates Lin28 activity during let-7a biogenesis and sheds light on the regulation of Lin28 in ES cells and carcinogenesis.

The impact of R213 mutation on p53-mediated p21 activity.

p53 is a transcriptional regulator in the nucleus that functions as a tumor suppressor and its mutations are frequently found in human tumors. It has been reported that p53 with R213Q mutation is exist in certain tumor cell lines and its methylation on R213 as well. However, the mechanisms and consequences of these modifications on p53 function are not fully understood. Mutations of p53 at R213Q (R/Q) and R213K (R/K) were respectively constructed and transfected into the p53 null H1299 cells. As shown in luciferase reporter assays, either R/Q or R/K disrupted the efficiency of p53 transactivation. EMSA and ChIP assays revealed that these mutants were less efficient in targeting the consensus binding sequences of p53 in the regulatory region of p21 gene. In addition, R/Q and R/K mutants attenuated the expression of p21 gene and counteracted the p53 mediated G1/S arrest to deliver a normal cell cycle progression as in the mock H1299 cells. Through this study, we have provided the first evidence on the pivotal role of arginine 213 that determines the p53 mediated functions of p21 in human cancer cells.

Adaptive changes in autophagy after UPS impairment in Parkinson's disease.

AIM: Ubiquitin-proteasome system (UPS) and autophagosome-lysosome pathway (ALP) are the most important machineries responsible for protein degradation in Parkinson's disease (PD). The aim of this study is to investigate the adaptive alterations in autophagy upon proteasome inhibition in dopaminergic neurons in vitro and in vivo. METHODS: Human dopaminergic neuroblastoma SH-SY5Y cells were treated with the proteasome inhibitor lactacystin (5 µmol/L) for 5, 12, or 24 h. The expression of autophagy-related proteins in the cells was detected with immunoblotting. UPS-impaired mouse model of PD was established by microinjection of lactacystin (2 µg) into the left hemisphere of C57BL/6 mice that were sacrificed 2 or 4 weeks later. The midbrain tissues were dissected to assess alterations in autophagy using immunofluorescence, immunoblotting and electron microscopy assays. RESULTS: Both in SH-SY5Y cells and in the midbrain of UPS-impaired mouse model of PD, treatment with lactacystin significantly increased the expression levels of LC3-I/II and Beclin 1, and reduced the levels of p-mTOR, mTOR and p62/SQSTM1. Furthermore, lactacystin treatment in UPS-impaired mouse model of PD caused significant loss of TH-positive neurons in the substantia nigra, and dramatically increased the number of autophagosomes in the left TH-positive neurons. CONCLUSION: Inhibition of UPS by lactacystin in dopaminergic neurons activates another protein degradation system, the ALP, which includes both the mTOR signaling pathway and Beclin 1-associated pathway.

Human PIH1 associates with histone H4 to mediate the glucose-dependent enhancement of pre-rRNA synthesis.

Ribosome biogenesis is critical in the growth of eukaryotic cells, in which the synthesis of precursor ribosomal RNA is the first and rate-limiting step. Here, we show that human PIH1 domain-containing protein 1 (PIH1) interacts directly with histone H4 and recruits the Brg1-SWI/SNF complex via SNF5 to human rRNA genes. This process is likely involved in PIH1-dependent DNase I-hypersensitive chromatin remodeling at the core promoter of the rRNA genes. PIH1 mediates the occupancy of not only the Brg1 complex but also the Pol I complex at the core promoter and enhances transcription initiation of rRNA genes. Additionally, the interaction between PIH1 and H4K16 expels TIP5, a component of the silencing nucleolar remodeling complex (NoRC), from the core region, suggesting that PIH1 is involved in the derepression of NoRC-silenced rRNA genes. These data indicate that PIH1 is a positive regulator of human rRNA genes and is of great importance for the recovery of human cells from nutrient starvation and the transition to glucose-induced exponential growth in vivo.

Differential effects of AdOx on gene expression in P19 embryonal carcinoma cells.

BACKGROUND: Pluripotent cells maintain a unique gene expression pattern and specific chromatin signature. In this study, we explored the effect of the methyltransferase inhibitor adenosine dialdehyde (AdOx) on pluripotency maintenance and gene expression in P19 embryonal carcinoma cells. RESULTS: After AdOx treatment, the pluripotency-related gene network became disordered, and the early developmental genes were released from the repression. Remarkably, AdOx caused contrasting effects on the expression of two key pluripotency genes, nanog and oct3/4, with the reduction of the repressive histone marks H3K27me3, H3K9me3 and H3K9me2 only in the nanog gene. CONCLUSIONS: Key pluripotency genes were controlled by different mechanisms, including the differential enrichment of repressive histone methylation marks. These data provided novel clues regarding the critical role of histone methylation in the maintenance of pluripotency and the determination of cell fate in P19 pluripotent cells.

The differential regulation of Gap43 gene in the neuronal differentiation of P19 cells.

Growth associated protein 43 (Gap43) is a neuron-specific phosphoprotein, which plays critical role in axon growth and synapses functions during neurogenesis. Here we identified two transcription start sites (TSSs) of the mouse Gap43 gene designated as a proximal site at +1, and a distal TSS at -414. RT-qPCR data reveal that the transcripts from +1 increase 10-fold on day-1 post-all-trans retinoic acid (RA) treatment, reached a peak value at day-4 and gradually reduced. By contrast, the distal TSS directs a late, remarkably sharp increase of the transcripts from the day-5 on. An intense signal of Gap43 at the neurites and neural network is determined by the efficient transcription of the distal promoter as shown in Northern blot and RT-qPCR assay. In addition, the targeting of p300 in combination with a differential enrichment of Brm to Brg1 change at the distal promoter region of the gene is induced under RA treatment. The over hundreds of GA rich stretches and the GAGAG elements located between the two TSSs may take parts in the differential transcription of the two TSSs of the Gap43. Our findings provide the first evidence on the identification and differential transcription of the two TSSs of the mouse Gap43 gene, and the preferential distribution of their protein products in the specific stages of RA induced P19 differentiation. These data suggest the efficient transcription of the distal promoter of Gap43 is an important mark for the transition of P19 cells from the progenitor stage into neuronal differentiation.

CARM1 mediates modulation of Sox2.

Sox2 is a key component of the transcription factor network that maintains the pluripotent state of embryonic stem cells (ESCs). Sox2 is regulated by multiple post-translational modifications, including ubiquitination, sumoylation, acetylation and phosphorylation. Here we report that Sox2 is in association with and methylated by coactivator-associated arginine methyltransferase 1 (CARM1), a protein arginine methyltransferase that plays a pivotal role in ESCs. We found that CARM1 facilitates Sox2-mediated transactivation and directly methylates Sox2 at arginine 113. This methylation event enhances Sox2 self-association. Furthermore, the physiological retention of Sox2 on chromatin restricts the Sox2 methylation level. Our study reveals the direct regulation of Sox2 by CARM1 that sheds lights on how arginine methylation signals are integrated into the pluripotent transcription factor network.

Mechanism of JmjC-containing protein Hairless in the regulation of vitamin D receptor function.

The JmjC-domain-containing protein Hairless (HR) and the vitamin D receptor (VDR) play a critical role in the maintenance of hair growth. Mutations in HR or VDR cause alopecia in humans and mice. Here we show that HR interacts with VDR and induces VDR relocalization in the nuclei. HR associates and colocalizes with nuclear receptor co-repressor (N-CoR) which is localized to subnuclear structures termed matrix-associated deacetylase (MAD) bodies. It is found that the HR mutants (C622G, N970S, D1012N, V1136D), associated with alopecia universalis congenita (AUC) or atrichia with papular lesions (APL), exhibit an abnormal subcellular distribution in addition to the impaired co-repressor activity with VDR. Studies on deletion mutants of HR indicate that the JmjC domain contributes to the co-repressor activity of HR. Our work provides new clues and evidence for the understanding on the role of HR in hair growth.

A switch from hBrm to Brg1 at IFNγ-activated sequences mediates the activation of human genes.

The SWI/SNF chromatin-remodeling complexes utilize energy from ATP hydrolysis to reposition nucleosomes and regulate the expression of human genes. Here, we studied the roles of human Brahma (hBrm) and Brahma-related gene 1 (Brg1), the ATPase subunits of the SWI/SNF complexes, in regulating human genes. Our results indicate that both hBrm and Brg1 interact with Signal transducer and activator of transcription (Stat) 1 in vitro. However, Stat1 in its native form only recruits hBrm to IFNγ-activated sequences (GAS) of individual genes; by contrast, in a stress-induced phosphorylated form, Stat1 mainly binds to Brg1. Under basal conditions, hBrm is recruited by native Stat1 to the GAS and exists in a mSin3/HDAC co-repressor complex on the hsp90α gene, which shows a compact chromatin structure. Upon heat-shock, hBrm is acetylated by p300 and dissociates from the co-repressor complex, which the phosphorylated Stat1 is increased, and binds and recruits Brg1 to the GAS, leading to elevated induction of the gene. This hBrm/Brg1 switch also occurs at the GAS of all of the three examined immune genes in heat-shocked cells; however, this switch only occurs in specific cell types upon exposure to IFNγ. Regardless of the stimulus, the hBrm/Brg1 switch at the GAS elicits an increase in gene activity. Our data are consistent with the hypothesis that the hBrm/Brg1 switch is an indicator of the responsiveness of a gene to heat-shock or IFNγ stimulation and may represent an "on-off switch" of gene expression in vivo.

[Effects of PTEN over-expression on phosphatidyl inositol 3-kinase/protein kinase B signal pathway in ovarian epithelial cancer cells].

OBJECTIVE: To evaluate the effect of exogenous wild PTEN gene stable transfected into human ovarian cancer cell line HO-8910 on phosphatidyl inositol 3-kinase (PI3K)/protein kinase B (Akt) signal pathway and cells proliferation. METHODS: Wild-type PTEN recombinant eukaryotic expression plasmid was constructed and then was transfected into HO-8910 cells by lipofectamine 2000. The expression of PTEN, Akt1, Akt2, PI3K mRNA and protein of PTEN were tested by reverse transcription (RT)-PCR and Western blot. The proliferation of HO-8910 after wild PTEN gene transfected was measured by methyl thiazolyl tetrazolium (MTT). RESULTS: Wild-type PTEN gene was successfully transfected into HO-8910 cells. The results of RT-PCR and western bolt showed that there were the significant expression high level of PTEN mRNA and protein after infected by wild-PTEN plasmid than those in the control [(17,372 ± 23) vs. (39 ± 1) vs. (78 ± 4) copies/ml, P < 0.05]. While the expression of mRNA of Akt1, Akt2 and PI3K were decreased clearly than those in the control [(28 ± 2) vs. (115 ± 5), (7 ± 1) vs. (18 ± 2), (61 ± 2) vs. (84 ± 2) copies/ml, all P < 0.05]. The proliferation rate of HO-8910 cells was obviously slower than those in the control (90 158 ± 47 vs. 148,251 ± 65 vs. 250,115 ± 62, P < 0.05). CONCLUSION: Transfection of PTEN may increase the expression of PTEN and inhibit the proliferation of HO-8910 cells, in which PI3K/Akt signal pathway is inhibit significantly.

Role of acetylated p53 in regulating the expression of map2 in retinoic acid-induced P19 cells.

OBJECTIVE: To investigate the regulatory mechanisms of acetylated p53 in the expression of microtubule-associated protein-2 (MAP2) in neuronal differentiation of P19 cells induced by all-trans retinoic acid (RA). METHODS: Neuronal differentiation of P19 cells was initiated with 4-day RA treatment. Immunofluorescence, real-time reverse transcription-polymerase chain reaction (RT-PCR) assay, and map2 promoter driven luciferase assay were performed to detect the expression and relative promoter activity of MAP2 in those RA-treated cells. Real-time PCR-based chromatin immunoprecipitation assay (ChIP) was carried out to reveal the specific recruitment of acetylated p53 onto its binding sites on map2 promoter. RESULTS: The expression of MAP2 was markedly increased in RA-induced P19 cells. The map2 mRNA increased 34-fold after 4 days of RA treatment and 730-fold 2 days after the treatment, compared with the cells without RA treatment (control). p53 was recruited to the promoter of map2 gene in acetylated form and thereby enhanced its promoter activity. p300/CBP associated factor (PCAF) was found induced in RA-treated cells and enriched in the nucleus, which might contribute to the acetylation of p53 in the regulation of map2 gene. CONCLUSIONS: Acetylated p53 may participate in regulating the expression of map2 in RA-induced differentiation of P19 cells. PCAF is possibly involved in this process by mediating the acetylation of p53.

Jmjd3 activates Mash1 gene in RA-induced neuronal differentiation of P19 cells.

Covalent modifications of histone tails have fundamental roles in chromatin structure and function. Tri-methyl modification on lysine 27 of histone H3 (H3K27me3) usually correlates with gene repression that plays important roles in cell lineage commitment and development. Mash1 is a basic helix-loop-helix regulatory protein that plays a critical role in neurogenesis, where it expresses as an early marker. In this study, we have shown a decreased H3K27me3 accompanying with an increased demethylase of H3K27me3 (Jmjd3) at the promoter of Mash1 can elicit a dramatically efficient expression of Mash1 in RA-treated P19 cells. Over-expression of Jmjd3 in P19 cells also significantly enhances the RA-induced expression and promoter activity of Mash1. By contrast, the mRNA expression and promoter activity of Mash1 are significantly reduced, when Jmjd3 siRNA or dominant negative mutant of Jmjd3 is introduced into the P19 cells. Chromatin immunoprecipitation assays show that Jmjd3 is efficiently recruited to a proximal upstream region of Mash1 promoter that is overlapped with the specific binding site of Hes1 in RA-induced cells. Moreover, the association between Jmjd3 and Hes1 is shown in a co-Immunoprecipitation assay. It is thus likely that Jmjd3 is recruited to the Mash1 promoter via Hes1. Our results suggest that the demethylase activity of Jmjd3 and its mediator Hes1 for Mash1 promoter binding are both required for Jmjd3 enhanced efficient expression of Mash1 gene in the early stage of RA-induced neuronal differentiation of P19 cells.