Human INO80/YY1 chromatin remodeling complex transcriptionally regulates the BRCA2- and CDKN1A-interacting protein (BCCIP) in cells

Yin Yang 1: Function, Mechanisms, and Glia

Yin Yang 1 is a ubiquitously expressed transcription factor that has been extensively studied given its particular dual transcriptional regulation. Yin Yang 1 is involved in various cellular processes like cell cycle progression, cell differentiation, DNA repair, cell survival and apoptosis among others. Its malfunction or alteration leads to disease and even to malignant transformation. This transcription factor is essential for the proper central nervous system development and function. The activity of Yin Yang 1 depends on its interacting partners, promoter environment and chromatin structure, however, its mechanistic activity is not completely understood. In this review, we briefly discuss the Yin Yang 1 structure, post-translational modifications, interactions, mechanistic functions and its participation in neurodevelopment. We also discuss its expression and critical involvement in the physiology and physiopathology of glial cells, summarizing the contribution of Yin Yang 1 on different aspects of cellular function.

Development and Validation of Prognostic Characteristics Associated With Chromatin Remodeling-Related Genes in Ovarian Cancer

BACKGROUND

Ovarian cancer (OC) is a prevalent malignant tumor in the field of gynecology, exhibiting the third highest incidence rate and the highest mortality rate among gynecological tumors. Chromatin remodeling accomplishes specific chromatin condensation at distinct genomic loci and plays an essential role in epigenetic regulation associated with various processes related to cancer development.

METHODS

Differentially expressed genes (DEGs) between OC and control samples were screened from The Cancer Genome Atlas (TCGA) and Genotype-Tissue Expression (GTEx) databases, combined with chromatin remodeling-related genes (CRRGs) obtained from the GeneCards database to identify differentially expressed CRRGs (DECRRGs). Enrichment analysis and protein-protein interaction (PPI) network were performed on the DECRRGs. Prognostic genes of OC were screened using univariate Cox and least absolute shrinkage and selection operator (Lasso) analyses. A risk model based on prognostic genes was developed, and the survival probability of OC patients in different risk groups was analyzed by Kaplan-Meier (KM) curve. Finally, the expression levels of prognostic genes were validated by quantitative real-time polymerase chain reaction (qRT-PCR) and western blotting.

RESULTS

In total, 7 potential prognostic genes associated with the progression of OC patients were obtained, including ARID1B, ATRX, CHRAC1, HDAC1, INO80, MBD2, and SS18. Based on the expression level of prognostic genes, OC patients were divided into high-risk group and low-risk group. Survival analysis indicated that patients classified into the high-risk group had higher mortality rates, which enables this prediction model to be utilized as an independent predictor of OC. Immunocorrelation analysis showed that low-risk patients were more likely to benefit from immunotherapy.

CONCLUSION

In this study, we have identified 7 prognostic genes, including ARID1B, ATRX, CHRAC1, HDAC1, INO80, MBD2, and SS18. Overall, our findings provided a foundation for further comprehension of the potential molecular mechanisms underlying OC pathogenesis and progression.

The Role of YY1 in the Regulation of LAG-3 Expression in CD8 T Cells and Immune Evasion in Cancer: Therapeutic Implications

The treatment of cancers with immunotherapies has yielded significant milestones in recent years. Amongst these immunotherapeutic strategies, the FDA has approved several checkpoint inhibitors (CPIs), primarily Anti-Programmed Death-1 (PD-1) and Programmed Death Ligand-1/2 (PDL-1/2) monoclonal antibodies, in the treatment of various cancers unresponsive to immune therapeutics. Such treatments resulted in significant clinical responses and the prolongation of survival in a subset of patients. However, not all patients responded to CPIs, due to various mechanisms of immune resistance. One such mechanism is that, in addition to PD-1 expression on CD8 T cells, other inhibitory receptors exist, such as Lymphocyte Activation Gene 3 (LAG-3), T cell Immunoglobulin Mucin 3 (TIM3), and T cell immunoreceptor with Ig and ITIM domains (TIGIT). These inhibitory receptors might be active in the presence of the above approved CPIs. Clearly, it is clinically challenging to block all such inhibitory receptors simultaneously using conventional antibodies. To circumvent this difficulty, we sought to target a potential transcription factor that may be involved in the molecular regulation of more than one inhibitory receptor. The transcription factor Yin Yang1 (YY1) was found to regulate the expression of PD-1, LAG-3, and TIM3. Therefore, we hypothesized that targeting YY1 in CD8 T cells should inhibit the expression of these receptors and, thus, prevent the inactivation of the anti-tumor CD8 T cells by these receptors, by corresponding ligands to tumor cells. This strategy should result in the prevention of immune evasion, leading to the inhibition of tumor growth. In addition, this strategy will be particularly effective in a subset of cancer patients who were unresponsive to approved CPIs. In this review, we discuss the regulation of LAG-3 by YY1 as proof of principle for the potential use of targeting YY1 as an alternative therapeutic approach to preventing the immune evasion of cancer. We present findings on the molecular regulations of both YY1 and LAG-3 expressions, the direct regulation of LAG-3 by YY1, the various approaches to targeting YY1 to evade immune evasion, and their clinical challenges. We also present bioinformatic analyses demonstrating the overexpression of LAG-3, YY1, and PD-L1 in various cancers, their associations with immune infiltrates, and the fact that when LAG-3 is hypermethylated in its promoter region it correlates with a better overall survival. Hence, targeting YY1 in CD8 T cells will result in restoring the anti-tumor immune response and tumor regression. Notably, in addition to the beneficial effects of targeting YY1 in CD8 T cells to inhibit the expression of inhibitory receptors, we also suggest targeting YY1 overexpressed in the tumor cells, which will also inhibit PD-L1 expression and other YY1-associated pro-tumorigenic activities.

MOF-mediated acetylation of CDK9 promotes global transcription by modulating P-TEFb complex formation

Cyclin-dependent kinase 9 (CDK9), a catalytic subunit of the positive transcription elongation factor b (P-TEFb) complex, is a global transcriptional elongation factor associated with cell proliferation. CDK9 activity is regulated by certain histone acetyltransferases, such as p300, GCN5 and P/CAF. However, the impact of males absent on the first (MOF) (also known as KAT8 or MYST1) on CDK9 activity has not been reported. Therefore, the present study aimed to elucidate the regulatory role of MOF on CDK9. We present evidence from systematic biochemical assays and molecular biology approaches arguing that MOF interacts with and acetylates CDK9 at the lysine 35 (i.e. K35) site, and that this acetyl-group can be removed by histone deacetylase HDAC1. Notably, MOF-mediated acetylation of CDK9 at K35 promotes the formation of the P-TEFb complex through stabilizing CDK9 protein and enhancing its association with cyclin T1, which further increases RNA polymerase II serine 2 residues levels and global transcription. Our study reveals for the first time that MOF promotes global transcription by acetylating CDK9, providing a new strategy for exploring the comprehensive mechanism of the MOF-CDK9 axis in cellular processes.

Role of YY1 in the Regulation of Anti-Apoptotic Gene Products in Drug-Resistant Cancer Cells

Cancer is a leading cause of death among the various diseases encountered in humans. Cancer is not a single entity and consists of numerous different types and subtypes that require various treatment regimens. In the last decade, several milestones in cancer treatments were accomplished, such as specific targeting agents or revitalizing the dormant anti-tumor immune response. These milestones have resulted in significant positive clinical responses as well as tumor regression and the prolongation of survival in subsets of cancer patients. Hence, in non-responding patients and non-responding relapsed patients, cancers develop intrinsic mechanisms of resistance to cell death via the overexpression of anti-apoptotic gene products. In parallel, the majority of resistant cancers have been reported to overexpress a transcription factor, Yin Yang 1 (YY1), which regulates the chemo-immuno-resistance of cancer cells to therapeutic anticancer cytotoxic agents. The relationship between the overexpression of YY1 and several anti-apoptotic gene products, such as B-cell lymphoma 2 protein (Bcl-2), B-cell lymphoma extra-large (Bcl-xL), myeloid cell leukemia 1 (Mcl-1) and survivin, is investigated in this paper. The findings demonstrate that these anti-apoptotic gene products are regulated, in part, by YY1 at the transcriptional, epigenetic, post-transcriptional and translational levels. While targeting each of the anti-apoptotic gene products individually has been examined and clinically tested for some, this targeting strategy is not effective due to compensation by other overexpressed anti-apoptotic gene products. In contrast, targeting YY1 directly, through small interfering RNAs (siRNAs), gene editing or small molecule inhibitors, can be therapeutically more effective and generalized in YY1-overexpressed resistant cancers.

The Non-Specific Lethal (NSL) Histone Acetyltransferase Complex Transcriptionally Regulates Yin Yang 1-Mediated Cell Proliferation in Human Cells

The human males absent on the first (MOF)-containing non-specific lethal (NSL) histone acetyltransferase (HAT) complex acetylates histone H4 at lysine K5, K8, and K16. This complex shares several subunits with other epigenetic regulatory enzymes, which highlights the complexity of its intracellular function. However, the effect of the NSL HAT complex on the genome and target genes in human cells is still unclear. By using a CRISPR/Cas9-mediated NSL3-knockout 293T cell line and chromatin immunoprecipitation-sequencing (ChIP-Seq) approaches, we identified more than 100 genes as NSL HAT transcriptional targets, including several transcription factors, such as Yin Yang 1 (YY1) which are mainly involved in cell proliferation, biological adhesion, and metabolic processes. We found here that the ChIP-Seq peaks of MOF and NSL3 co-localized with H4K16ac, H3K4me2, and H3K4me3 at the transcriptional start site of YY1. In addition, both the mRNA and protein expression levels of YY1 were regulated by silencing or overexpressing NSL HAT. Interestingly, the expression levels of cell division cycle 6, a downstream target gene of YY1, were regulated by MOF or NSL3. In addition, the suppressed clonogenic ability of HepG2 cells caused by siNSL3 was reversed by overexpressing YY1, suggesting the involvement of YY1 in NSL HAT functioning. Additionally, de novo motif analysis of MOF and NSL3 targets indicated that the NSL HAT complex may recognize the specific DNA-binding sites in the promoter region of target genes in order to regulate their transcription.

HIRA complex presets transcriptional potential through coordinating depositions of the histone variants H3.3 and H2A.Z on the poised genes in mESCs

Histone variants have been implicated in regulating chromatin dynamics and genome functions. Previously, we have shown that histone variant H3.3 actively marks enhancers and cooperates with H2A.Z at promoters to prime the genes into a poised state in mouse embryonic stem cells (mESCs). However, how these two important histone variants collaboratively function in this process still remains elusive. In this study, we found that depletion of different components of HIRA complex, a specific chaperone of H3.3, results in significant decreases of H2A.Z enrichment at genome scale. In addition, CUT&Tag data revealed a genomic colocalization between HIRA complex and SRCAP complex. In vivo and in vitro biochemical assays verified that HIRA complex could interact with SRCAP complex through the Hira subunit. Furthermore, our chromatin accessibility and transcription analyses demonstrated that HIRA complex contributed to preset a defined chromatin feature around TSS region for poising gene transcription. In summary, our results unveiled that while regulating the H3.3 incorporation in the regulatory regions, HIRA complex also collaborates with SRCAP to deposit H2A.Z onto the promoters, which cooperatively determines the transcriptional potential of the poised genes in mESCs.

The Protective Role of Yin-Yang 1 in Cardiac Injury and Remodeling After Myocardial Infarction

Background Exploring potential therapeutic target is of great significance for myocardial infarction (MI) and post-MI heart failure. Transcription factor Yin-Yang 1 (YY1) is an essential regulator of apoptosis and angiogenesis, but its role in MI is unclear. Methods and Results The expression of YY1 was assessed in the C57BL/6J mouse heart following MI. Overexpression or silencing of YY1 in the mouse heart was achieved by adeno-associated virus 9 injection. The survival, cardiac function, and scar size, as well as the apoptosis, angiogenesis, cardiac fibrosis, T helper 2 lymphocyte cytokine production, and macrophage polarization were assessed. The effects of YY1 on Akt phosphorylation and vascular endothelial growth factor production were also investigated. The expression of YY1 in heart was significantly stimulated by MI. The survival rate, cardiac function, scar size, and left ventricular volume of mice were improved by YY1 overexpression but worsened by YY1 silencing. YY1 alleviated cardiac apoptosis and fibrosis, promoted angiogenesis, T helper 2 cytokine production, and M2 macrophage polarization in the post-MI heart, it also enhanced the tube formation and migration ability of endothelial cells. Enhanced Akt phosphorylation, along with the increased vascular endothelial growth factor levels were observed in presence of YY1 overexpression. Conclusions YY1 ameliorates cardiac injury and remodeling after MI by repressing cardiomyocyte apoptosis and boosting angiogenesis, which might be ascribed to the enhancement of Akt phosphorylation and the subsequent vascular endothelial growth factor up-regulation. Increased T helper 2 cytokine production and M2 macrophage polarization may also be involved in YY1's cardioprotective effects. These findings supported YY1 as a potential target for therapeutic investigation of MI.

YY1 Silencing Induces 5-Fluorouracil-Resistance and BCL2L15 Downregulation in Colorectal Cancer Cells: Diagnostic and Prognostic Relevance

Colorectal cancer (CRC) is characterized by genetic heterogeneity and is often diagnosed at an advanced stage. Therefore, there is a need to identify novel predictive markers. Yin Yang 1 (YY1) is a transcription factor playing a dual role in cancer. The present study aimed to investigate whether YY1 expression levels influence CRC cell response to therapy and to identify the transcriptional targets involved. The diagnostic and prognostic values of YY1 and the identified factor(s) in CRC patients were also explored. Silencing of YY1 increased the resistance to 5-Fluorouracil-induced cytotoxicity in two out of four CRC cells with different genotypes. BCL2L15/Bfk pro-apoptotic factor was found selectively expressed in the responder CRC cells and downregulated upon YY1 knockdown. CRC dataset analyses corroborated a tumor-suppressive role for both YY1 and BCL2L15 whose expressions were inversely correlated with aggressiveness. CRC single-cell sequencing dataset analyses demonstrated higher co-expression levels of both YY1 and BCL2L15 within defined tumor cell clusters. Finally, elevated levels of YY1 and BCL2L15 in CRC patients were associated with larger relapse-free survival. Given their observed anti-cancer role, we propose YY1 and BCL2L15 as candidate diagnostic and prognostic CRC biomarkers.

HIF-1: structure, biology and natural modulators

Hypoxia-inducible factor 1 (HIF-1), as a main transcriptional regulator of metabolic adaptation to changes in the oxygen environment, participates in many physiological and pathological processes in the body, and is closely related to the pathogenesis of many diseases. This review outlines the mechanisms of HIF-1 activation, its signaling pathways, natural inhibitors, and its roles in diseases. This article can provide new insights in the diagnosis and treatment of human diseases, and recent progress on the development of HIF-1 inhibitors.

KAT8/MOF-Mediated Anti-Cancer Mechanism of Gemcitabine in Human Bladder Cancer Cells

Histone acetylation is a well-characterized epigenetic modification controlled by histone acetyltransferases (HATs) and histone deacetylases (HDACs). Imbalanced histone acetylation has been observed in many primary cancers. Therefore, efforts have been made to find drugs or small molecules such as HDAC inhibitors that can revert acetylation levels to normal in cancer cells. We observed dose-dependent reduction in the endogenous and exogenous protein expression levels of KAT8 (also known as human MOF), a member of the MYST family of HATs, and its corresponding histone acetylation at H4K5, H4K8, and H4K16 in chemotherapy drug gemcitabine (GEM)-exposed T24 bladder cancer (BLCA) cells. Interestingly, the reduction in MOF and histone H4 acetylation was inversely proportional to GEM-induced γH2AX, an indicator of chemotherapy drug effectiveness. Furthermore, pGL4-MOF-Luc reporter activities were significantly inhibited by GEM, thereby suggesting that GEM utilizes an MOF-mediated anti-BLCA mechanism of action. In the CCK-8, wound healing assays and Transwell^® experiments, the additive effects on cell proliferation and migration were observed in the presence of exogenous MOF and GEM. In addition, the promoted cell sensitivity to GEM by exogenous MOF in BLCA cells was confirmed using an Annexin V-FITC/PI assay. Taken together, our results provide the theoretical basis for elucidating the anti-BLCA mechanism of GEM.

Identification of prognostic chromatin-remodeling genes in clear cell renal cell carcinoma

The aim of this study was to investigate the effects of chromatin-remodeling genes on the prognosis of patients with clear cell renal cell carcinoma (ccRCC). In TCGA-KIRC patients, two subgroups based on 86 chromatin-remodeling genes were established. The random forest algorithm was used for feature selection to identify BPTF, SIN3A and CNOT1 as characterized chromatin remodelers in ccRCC with good prognostic value. YY1 was indicated to be a transcription factor of genes highly related to BPTF, SIN3A and CNOT1. Functional annotations indicated that BPTF, SIN3A, CNOT1 and YY1 are all involved in the ubiquitin-mediated proteolysis process and that high expression of any of the five associated E3 ubiquitin ligases found in the pathway suggests a good prognosis. Protein network analysis indicated that BPTF has a targeted regulatory effect on YY1. Another independent dataset from International Cancer Genome Consortium (ICGC) showed a strong consistency with results in TCGA. In conclusion, we demonstrate that BPTF, SIN3A and CNOT1 are novel prognostic factors that predict good survival in ccRCC. We predicted that the good prognostic value of chromatin-remodeling genes BPTF and SIN3A is related to the regulation of YY1 and that YY1 regulates E3 ubiquitin ligases for further degradation of oncoproteins in ccRCC.

The Emerging Roles of ATP-Dependent Chromatin Remodeling Complexes in Pancreatic Cancer

Pancreatic cancer is an aggressive cancer with low survival rates. Genetic and epigenetic dysregulation has been associated with the initiation and progression of pancreatic tumors. Multiple studies have pointed to the involvement of aberrant chromatin modifications in driving tumor behavior. ATP-dependent chromatin remodeling complexes regulate chromatin structure and have critical roles in stem cell maintenance, development, and cancer. Frequent mutations and chromosomal aberrations in the genes associated with subunits of the ATP-dependent chromatin remodeling complexes have been detected in different cancer types. In this review, we summarize the current literature on the genomic alterations and mechanistic studies of the ATP-dependent chromatin remodeling complexes in pancreatic cancer. Our review is focused on the four main subfamilies: SWItch/sucrose non-fermentable (SWI/SNF), imitation SWI (ISWI), chromodomain-helicase DNA-binding protein (CHD), and INOsitol-requiring mutant 80 (INO80). Finally, we discuss potential novel treatment options that use small molecules to target these complexes.

YY1/BCCIP Coordinately Regulates P53-Responsive Element (p53RE)-Mediated Transactivation of p21Waf1/Cip1

Transactivation of p21 (cyclin-dependent kinase inhibitor 1A, CDKN1A) is closely related to the recruitment of transcription cofactors at the p53 responsive elements (p53REs) in its promoter region. Human chromatin remodeling enzyme INO80 can be recruited to the p53REs of p21 promoter and negatively regulates p21. As one of the key subunits of the INO80 complex, YY1 has also been confirmed to bind to the p53RE sites of p21 promoter. Importantly, YY1 was recently reported to be bound and stabilized by BCCIP (BRCA2 and CDKN1A-interacting protein). Therefore, we hypothesized that the YY1/BCCIP complex plays an important role in regulating the transactivation of p21. Here we present evidence that the YY1/BCCIP complex coordinatively regulates p53RE-mediated p21 transactivation. We first confirmed the cross-interaction between YY1, BCCIP, and p53, suggesting an intrinsic link between three proteins in the regulation of p21 transcription. In dual luciferase assays, YY1 inhibited p53RE-mediated luciferase activity, whereas BCCIP revealed the opposite effect. More interestingly, the region 146–270 amino acids of YY1, which bound to BCCIP, increased p53-mediated luciferase activity, indicating the complexity of the YY1/BCCIP complex in co-regulating p21 transcription. Further in-depth research confirmed the co-occupancy of YY1/BCCIP with p53 at the p53RE-proximal region of p21. Lentiviral-mediated knockdown of BCCIP inhibited the recruitment of p53 and YY1 at the p53RE proximal region of p21; however, this phenomenon was reversed by expressing exogenous YY1, suggesting the collaborative regulation of YY1/BCCIP complex in p53RE-mediated p21 transcription. These data provide new insights into the transcriptional regulation of p21 by the YY1/BCCIP complex.

Enhancer function regulated by combinations of transcription factors and cofactors

Regulation of the expression of diverse genes is essential for making possible the complexity of higher organisms, and the temporal and spatial regulation of gene expression allows for the alteration of cell types and growth patterns. A critical component of this regulation is the DNA sequence-specific binding of transcription factors (TFs). However, most TFs do not independently participate in gene transcriptional regulation, because they lack an effector function. Instead, TFs are thought to work by recruiting cofactors, including Mediator complex (Mediator), chromatin-remodeling complexes (CRCs), and histone-modifying complexes (HMCs). Mediator associates with the majority of transcribed genes and acts as an integrator of multiple signals. On the other hand, CRCs and HMCs are selectively recruited by TFs. Although all the pairings between TFs and CRCs or HMCs are not fully known, there are a growing number of established TF-CRC and TF-HMC combinations. In this review, we focused on the most important of these pairings and discuss how they control gene expression.

BCCIP binds to and activates its promoter in a YY1-dependent fashion in HCT116 cells

The restriction of Yin Yang 1 (YY1) at BRCA2 and CDKN1A/p21-interacting protein (BCCIP) transcriptional start site (TSS) proximal region in several human cancer cell lines was found by analyzation of ChIP-Seq database from UCSC Genome Browser (http://genome.ucsc.edu). However, whether the stabilization of YY1 by BCCIP impacts its recruitment in the BCCIP promoter region is unclear. Here, we present evidence that transcriptional regulation of YY1 on BCCIP is closely related to YY1 stability in HCT116 human colon cancer cells. YY1 stabilization was in turn regulated by BCCIP, suggesting the existence of a BCCIP-YY1 feedback loop in regulating BCCIP transcription by the YY1. Overexpression of BCCIP stabilized YY1 while knockdown of BCCIP reduced YY1 protein level. In addition, direct interaction between YY1 and BCCIP was confirmed by coimmunoprecipitation approach. Also, the N-terminus region of BCCIP, including the internal conserved domain (ICD), was responsible for binding with the amino acid 146-270 of YY1. More importantly, YY1 stability was related to the BCCIP/ICD domain-mediated YY1 ubiquitination pathway. Moreover, a limited BCCIP promoter region containing YY1 binding site (CCGCCATC) was tightly associated with the pGL4-BCCIP-Luc luciferase activity. In ChIP assays, shBCCIP lentiviral-mediated YY1 instability decreased recruitment of the YY1 at BCCIP TSS proximal region, which could not be restored by YY1 overexpression. Furthermore, knockdown of YY1 inhibited the binding of BCCIP itself at BCCIP promoter region proximal to TSS, demonstrating that transcriptional regulation of the YY1 on BCCIP can be modulated by BCCIP itself in a YY1-dependent fashion.

c-Abl phosphorylation of Yin Yang 1's conserved tyrosine 254 in the spacer region modulates its transcriptional activity

Yin Yang 1 (YY1) is a multifunctional transcription factor that can activate or repress transcription depending on the promotor and/or the co-factors recruited. YY1 is phosphorylated in various signaling pathways and is critical for different biological functions including embryogenesis, apoptosis, proliferation, cell-cycle regulation and tumorigenesis. Here we report that YY1 is a substrate for c-Abl kinase phosphorylation at conserved residue Y254 in the spacer region. Pharmacological inhibition of c-Abl kinase by imatinib, nilotinib and GZD824, knock-down of c-Abl using siRNA, and the use of c-Abl kinase-dead drastically reduces tyrosine phosphorylation of YY1. Both radioactive and non-radioactive in vitro kinase assays, as well as co-immunoprecipitation in different cell lines, show that the target of c-Abl phosphorylation is tyrosine residue 254. c-Abl phosphorylation has little effect on YY1 DNA binding ability or cellular localization in asynchronous cells. However, functional studies reveal that c-Abl mediated phosphorylation of YY1 regulates YY1's transcriptional ability in vivo. In conclusion, we demonstrate the novel role of c-Abl kinase in regulation of YY1's transcriptional activity, linking YY1 regulation with c-Abl tyrosine kinase signaling pathways.

The effect of 8-OH-DPAT and dapoxetine on gene expression in the brain of male rats during ejaculation

The 5-HT_1A receptor agonist 8-hydroxy-2-[di-n-propylamino] tetralin (8-OH-DPAT) promotes ejaculation of male rats, whereas dapoxetine delays this process. However, the gene expression profile of the brain at ejaculation following administrationof these two compounds has not been fully elucidated. In the present study, a transcriptomic BodyMap was generated by conducting mRNA-Seq on brain samples of male Sprague–Dawley rats. The study included four groups: pre-copulatory control (CK) group, ejaculation (EJ) group, 0.5 mg/kg 8-OH-DPAT-ejaculation group (DPAT), and 60 mg/kg dapoxetine-ejaculation (DAP) group. The resulting analysis generated an average of approximately 47 million sequence reads. Significant differences in the gene expression profiles of the aforementioned groups were observed in the EJ (257 genes), DPAT (349 genes) and the DAP (207 genes) compared with the control rats. The results indicate that the expression of Drd1 and Slc6a3 was significantly different after treatment with 8-OH-DPAT, whereas the expression of Drd4 was significantly different after treatment with dapoxetine. Other genes, such as Wnt9b, Cdkn1a and Fosb, exhibited significant differences in expression after the two treatments and are related to bladder cancer, renal cell carcinoma and sexual addiction. The present study reveals the basic pattern of gene expression that was activated at ejaculation in the presence of 8-OH-DPAT or dapoxetine, providing preliminary gene expression information during rat ejaculation.