RESUMO
Oligodendrocyte myelination and remyelination after injury are intricately regulated by various intrinsic and extrinsic factors, including transcriptional regulators. Among these, the zinc-finger protein ZFP488 is an oligodendrocyte-enriched transcriptional regulator that promotes oligodendrocyte differentiation in the developing neural tube and in oligodendroglial cell lines. However, the specific in vivo genetic requirements for ZFP488 during oligodendrocyte development and remyelination have not been defined. To address this gap, we generated a lineage-traceable ZFP488 knock-out mouse line, wherein a H2b-GFP reporter replaces the ZFP488-coding region. Using these mice of either sex, we examined the dynamics of ZFP488 expression from the endogenous promoter in the developing central nervous system (CNS). We observed a unique expression pattern in the oligodendrocyte lineage, with ZFP488 expression particularly enriched in differentiated oligodendrocytes. ZFP488 loss resulted in delayed myelination in the developing CNS and impaired remyelination after demyelinating injury in the brain. Integrated transcriptomic and genomic profiling further revealed that ZFP488 loss decreased expression of myelination-associated genes but not oligodendrocyte progenitor-associated genes, suggesting that ZFP488 serves as a positive regulator of myelination by regulating maturation programs. Thus, our genetic loss-of-function study revealed that ZFP488 regulates a stage-dependent differentiation program that controls the timing of CNS myelination and remyelination.Significance statement Precise timing of myelination is essential for efficient neural communication and is linked to the development of cognitive and motor skills as well as myelin repair after injury. ZFP488 is a transcriptional regulator enriched in oligodendrocytes, however its in vivo functions remain unclear. By generating ZFP488 loss-of-function mice, we demonstrated that ZFP488 is critical for the timing of myelination and remyelination and that its loss impaired the initial differentiation of oligodendrocytes but not their precursor formation and proliferation. Transcriptomic profiling showed that ZFP488 functions as a positive regulator of myelination by modulating oligodendrocyte maturation programs. Thus, our findings underscore the important role of ZFP488 in myelination and the potential of ZFP488 augmentation as an avenue to enhance oligodendrocyte regeneration.
RESUMO
Remyelination failure in diseases like multiple sclerosis (MS) was thought to involve suppressed maturation of oligodendrocyte precursors; however, oligodendrocytes are present in MS lesions yet lack myelin production. We found that oligodendrocytes in the lesions are epigenetically silenced. Developing a transgenic reporter labeling differentiated oligodendrocytes for phenotypic screening, we identified a small-molecule epigenetic-silencing-inhibitor (ESI1) that enhances myelin production and ensheathment. ESI1 promotes remyelination in animal models of demyelination and enables de novo myelinogenesis on regenerated CNS axons. ESI1 treatment lengthened myelin sheaths in human iPSC-derived organoids and augmented (re)myelination in aged mice while reversing age-related cognitive decline. Multi-omics revealed that ESI1 induces an active chromatin landscape that activates myelinogenic pathways and reprograms metabolism. Notably, ESI1 triggered nuclear condensate formation of master lipid-metabolic regulators SREBP1/2, concentrating transcriptional co-activators to drive lipid/cholesterol biosynthesis. Our study highlights the potential of targeting epigenetic silencing to enable CNS myelin regeneration in demyelinating diseases and aging.
Assuntos
Epigênese Genética , Bainha de Mielina , Oligodendroglia , Remielinização , Animais , Bainha de Mielina/metabolismo , Humanos , Camundongos , Remielinização/efeitos dos fármacos , Oligodendroglia/metabolismo , Sistema Nervoso Central/metabolismo , Camundongos Endogâmicos C57BL , Rejuvenescimento , Células-Tronco Pluripotentes Induzidas/metabolismo , Células-Tronco Pluripotentes Induzidas/efeitos dos fármacos , Proteína de Ligação a Elemento Regulador de Esterol 1/metabolismo , Organoides/metabolismo , Organoides/efeitos dos fármacos , Doenças Desmielinizantes/metabolismo , Doenças Desmielinizantes/genética , Diferenciação Celular/efeitos dos fármacos , Bibliotecas de Moléculas Pequenas/farmacologia , Masculino , Regeneração/efeitos dos fármacos , Esclerose Múltipla/metabolismo , Esclerose Múltipla/genética , Esclerose Múltipla/tratamento farmacológico , Esclerose Múltipla/patologiaRESUMO
BACKGROUND: Diffuse intrinsic pontine gliomas (DIPG/DMG) are devastating pediatric brain tumors with extraordinarily limited treatment options and uniformly fatal prognosis. Histone H3K27M mutation is a common recurrent alteration in DIPG and disrupts epigenetic regulation. We hypothesize that genome-wide H3K27M-induced epigenetic dysregulation makes tumors vulnerable to epigenetic targeting. METHODS: We performed a screen of compounds targeting epigenetic enzymes to identify potential inhibitors for the growth of patient-derived DIPG cells. We further carried out transcriptomic and genomic landscape profiling including RNA-seq and CUT&RUN-seq as well as shRNA-mediated knockdown to assess the effects of chaetocin and SUV39H1, a target of chaetocin, on DIPG growth. RESULTS: High-throughput small-molecule screening identified an epigenetic compound chaetocin as a potent blocker of DIPG cell growth. Chaetocin treatment selectively decreased proliferation and increased apoptosis of DIPG cells and significantly extended survival in DIPG xenograft models, while restoring H3K27me3 levels. Moreover, the loss of H3K9 methyltransferase SUV39H1 inhibited DIPG cell growth. Transcriptomic and epigenomic profiling indicated that SUV39H1 loss or inhibition led to the downregulation of stemness and oncogenic networks including growth factor receptor signaling and stemness-related programs; however, D2 dopamine receptor (DRD2) signaling adaptively underwent compensatory upregulation conferring resistance. Consistently, a combination of chaetocin treatment with a DRD2 antagonist ONC201 synergistically increased the antitumor efficacy. CONCLUSIONS: Our studies reveal a therapeutic vulnerability of DIPG cells through targeting the SUV39H1-H3K9me3 pathway and compensatory signaling loops for treating this devastating disease. Combining SUV39H1-targeting chaetocin with other agents such as ONC201 may offer a new strategy for effective DIPG treatment.
Assuntos
Neoplasias do Tronco Encefálico , Glioma Pontino Intrínseco Difuso , Imidazóis , Piridinas , Pirimidinas , Criança , Humanos , Epigênese Genética , Histonas/genética , Glioma Pontino Intrínseco Difuso/genética , Neoplasias do Tronco Encefálico/tratamento farmacológico , Neoplasias do Tronco Encefálico/genética , Neoplasias do Tronco Encefálico/patologia , Metiltransferases/genética , Metiltransferases/metabolismo , Proteínas Repressoras/genética , Proteínas Repressoras/metabolismo , PiperazinasRESUMO
MYC-driven medulloblastomas are highly aggressive childhood brain tumors, however, the molecular and genetic events triggering MYC amplification and malignant transformation remain elusive. Here we report that mutations in CTDNEP1, a CTD nuclear-envelope-phosphatase, are the most significantly enriched recurrent alterations in MYC-driven medulloblastomas, and define high-risk subsets with poorer prognosis. Ctdnep1 ablation promotes the transformation of murine cerebellar progenitors into Myc-amplified medulloblastomas, resembling their human counterparts. CTDNEP1 deficiency stabilizes and activates MYC activity by elevating MYC serine-62 phosphorylation, and triggers chromosomal instability to induce p53 loss and Myc amplifications. Further, phosphoproteomics reveals that CTDNEP1 post-translationally modulates the activities of key regulators for chromosome segregation and mitotic checkpoint regulators including topoisomerase TOP2A and checkpoint kinase CHEK1. Co-targeting MYC and CHEK1 activities synergistically inhibits CTDNEP1-deficient MYC-amplified tumor growth and prolongs animal survival. Together, our studies demonstrate that CTDNEP1 is a tumor suppressor in highly aggressive MYC-driven medulloblastomas by controlling MYC activity and mitotic fidelity, pointing to a CTDNEP1-dependent targetable therapeutic vulnerability.
Assuntos
Neoplasias Encefálicas , Neoplasias Cerebelares , Meduloblastoma , Humanos , Camundongos , Animais , Criança , Meduloblastoma/patologia , Monoéster Fosfórico Hidrolases/genética , Neoplasias Cerebelares/patologia , Transformação Celular Neoplásica/genética , Instabilidade Genômica , Proteínas Proto-Oncogênicas c-myc/genética , Fosfoproteínas Fosfatases/genéticaRESUMO
Nuclear localization of HIPPO-YAP fusion proteins has been implicated in supratentorial ependymoma development. Here, unexpectedly, we find that liquid-liquid phase separation, rather than nuclear localization, of recurrent patient-derived YAP fusions, YAP-MAMLD1 and C11ORF95-YAP, underlies ependymoma tumourigenesis from neural progenitor cells. Mutagenesis and chimaera assays demonstrate that an intrinsically disordered region promotes oligomerization of the YAP fusions into nuclear, puncta-like, membrane-less condensates. Oligomerization and nuclear condensates induced by YAP fusion with a coiled-coil domain of transcriptional activator GCN4 also promote ependymoma formation. YAP-MAMLD1 concentrates transcription factors and co-activators, including BRD4, MED1 and TEAD, in condensates while excluding transcriptional repressive PRC2, and induces long-range enhancer-promoter interactions that promote transcription and oncogenic programmes. Blocking condensate-mediated transcriptional co-activator activity inhibits tumourigenesis, indicating a critical role of liquid phase separation for YAP fusion oncogenic activity in ependymoma. YAP fusions containing the intrinsically disordered region features are common in human tumours, suggesting that nuclear condensates could be targeted to treat YAP-fusion-induced cancers.
Assuntos
Ependimoma , Fatores de Transcrição , Humanos , Proteínas Adaptadoras de Transdução de Sinal/genética , Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Carcinogênese/genética , Proteínas de Ciclo Celular/metabolismo , Transformação Celular Neoplásica/genética , Transformação Celular Neoplásica/metabolismo , Ependimoma/genética , Ependimoma/metabolismo , Ependimoma/patologia , Proteínas Nucleares/metabolismo , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Proteínas de Sinalização YAP , Núcleo Celular/metabolismo , Transcrição GênicaRESUMO
Malignant gliomas such as glioblastoma are highly heterogeneous with distinct cells of origin and varied genetic alterations. It remains elusive whether the specific states of neural cell lineages are differentially susceptible to distinct genetic alterations during malignant transformation. Here, an analysis of The Cancer Genome Atlas databases revealed that comutations of PTEN and TP53 are most significantly enriched in human high-grade gliomas. Therefore, we selectively ablated Pten and Trp53 in different progenitors to determine which cell lineage states are susceptible to malignant transformation. Mice with PTEN/p53 ablation mediated by multilineage-expressing human GFAP (hGFAP) promoter-driven Cre developed glioma but with incomplete penetrance and long latency. Unexpectedly, ablation of Pten and Trp53 in Nestin+ neural stem cells (NSC) or Pdgfra+/NG2+ committed oligodendrocyte precursor cells (OPC), two major cells of origin in glioma, did not induce glioma formation in mice. Strikingly, mice lacking Pten and Trp53 in Olig1+/Olig2+ intermediate precursors (pri-OPC) prior to the committed OPCs developed high-grade gliomas with 100% penetrance and short latency. The resulting tumors exhibited distinct tumor phenotypes and drug sensitivities from NSC- or OPC-derived glioma subtypes. Integrated transcriptomic and epigenomic analyses revealed that PTEN/p53-loss induced activation of oncogenic pathways, including HIPPO-YAP and PI3K signaling, to promote malignant transformation. Targeting the core regulatory circuitries YAP and PI3K signaling effectively inhibited tumor cell growth. Thus, our multicell state in vivo mutagenesis analyses suggests that transit-amplifying states of Olig1/2 intermediate lineage precursors are predisposed to PTEN/p53-loss-induced transformation and gliomagenesis, pointing to subtype-specific treatment strategies for gliomas with distinct genetic alterations. SIGNIFICANCE: Multiple progenitor-state mutagenesis reveal that Olig1/2-expressing intermediate precursors are highly susceptible to PTEN/p53-loss-mediated transformation and impart differential drug sensitivity, indicating tumor-initiating cell states and genetic drivers dictate glioma phenotypes and drug responses. See related commentary by Zamler and Hu, p. 807.
Assuntos
Neoplasias Encefálicas , Glioblastoma , Glioma , Animais , Humanos , Camundongos , Fatores de Transcrição Hélice-Alça-Hélice Básicos/metabolismo , Neoplasias Encefálicas/patologia , Transformação Celular Neoplásica/genética , Transformação Celular Neoplásica/patologia , Glioblastoma/patologia , Glioma/patologia , Proteínas do Tecido Nervoso/genética , Proteínas do Tecido Nervoso/metabolismo , Fosfatidilinositol 3-Quinases/metabolismo , PTEN Fosfo-Hidrolase/genética , PTEN Fosfo-Hidrolase/metabolismo , Proteína Supressora de Tumor p53/genética , Proteína Supressora de Tumor p53/metabolismoRESUMO
Medulloblastoma (MB) is the most common malignant childhood brain tumour1,2, yet the origin of the most aggressive subgroup-3 form remains elusive, impeding development of effective targeted treatments. Previous analyses of mouse cerebella3-5 have not fully defined the compositional heterogeneity of MBs. Here we undertook single-cell profiling of freshly isolated human fetal cerebella to establish a reference map delineating hierarchical cellular states in MBs. We identified a unique transitional cerebellar progenitor connecting neural stem cells to neuronal lineages in developing fetal cerebella. Intersectional analysis revealed that the transitional progenitors were enriched in aggressive MB subgroups, including group 3 and metastatic tumours. Single-cell multi-omics revealed underlying regulatory networks in the transitional progenitor populations, including transcriptional determinants HNRNPH1 and SOX11, which are correlated with clinical prognosis in group 3 MBs. Genomic and Hi-C profiling identified de novo long-range chromatin loops juxtaposing HNRNPH1/SOX11-targeted super-enhancers to cis-regulatory elements of MYC, an oncogenic driver for group 3 MBs. Targeting the transitional progenitor regulators inhibited MYC expression and MYC-driven group 3 MB growth. Our integrated single-cell atlases of human fetal cerebella and MBs show potential cell populations predisposed to transformation and regulatory circuitries underlying tumour cell states and oncogenesis, highlighting hitherto unrecognized transitional progenitor intermediates predictive of disease prognosis and potential therapeutic vulnerabilities.
Assuntos
Neoplasias Encefálicas , Transformação Celular Neoplásica , Feto , Meduloblastoma , Humanos , Neoplasias Encefálicas/patologia , Transformação Celular Neoplásica/patologia , Neoplasias Cerebelares/patologia , Cerebelo/citologia , Cerebelo/patologia , Feto/citologia , Feto/patologia , Meduloblastoma/patologia , Células-Tronco Neurais/citologia , Células-Tronco Neurais/patologia , PrognósticoRESUMO
Lysyl oxidase-like 2 (LOXL2) is a member of the scavenger receptor cysteine-rich (SRCR) repeat carrying LOX family. Although LOXL2 is suspected to be involved in histone association and chromatin modification, the role of LOXL2 in epigenetic regulation during tumorigenesis and cancer progression remains unclear. Here, we report that nuclear LOXL2 associates with histone H3 and catalyzes H3K36ac deacetylation and deacetylimination. Both the N-terminal SRCR repeats and the C-terminal catalytic domain of LOXL2 carry redundant deacetylase catalytic activity. Overexpression of LOXL2 markedly reduced H3K36 acetylation and blocked H3K36ac-dependent transcription of genes, including c-MYC, CCND1, HIF1A, and CD44. Consequently, LOXL2 overexpression reduced cancer cell proliferation in vitro and inhibited xenograft tumor growth in vivo. In contrast, LOXL2 deficiency resulted in increased H3K36 acetylation and aberrant expression of H3K36ac-dependent genes involved in multiple oncogenic signaling pathways. Female LOXL2-deficient mice spontaneously developed uterine hypertrophy and uterine carcinoma. Moreover, silencing LOXL2 in cancer cells enhanced tumor progression and reduced the efficacy of cisplatin and anti-programmed cell death 1 (PD-1) combination therapy. Clinically, low nuclear LOXL2 expression and high H3K36ac levels corresponded to poor prognosis in uterine endometrial carcinoma patients. These results suggest that nuclear LOXL2 restricts cancer development in the female reproductive system via the regulation of H3K36ac deacetylation. SIGNIFICANCE: LOXL2 loss reprograms the epigenetic landscape to promote uterine cancer initiation and progression and repress the efficacy of anti-PD-1 immunotherapy, indicating that LOXL2 is a tumor suppressor.
Assuntos
Aminoácido Oxirredutases , Epigênese Genética , Humanos , Camundongos , Feminino , Animais , Aminoácido Oxirredutases/genética , Aminoácido Oxirredutases/metabolismo , Acetilação , Histonas/metabolismo , Hipertrofia/genética , Expressão GênicaRESUMO
T helper 1 (Th1) immunity is typically viewed as a critical adaptation by vertebrates against intracellular pathogens. Identifying novel targets to enhance Th1 cell differentiation and function is increasingly important for anti-infection immunity. Here, through small-molecule screening focusing on epigenetic modifiers during the in vitro Th1 cell differentiation process, we identified that the selective histone deacetylase 6 (HDAC6) inhibitors ricolinostat and nexturastat A (Nex A) promoted Th1 cell differentiation. HDAC6-depleted mice exhibit elevation of Th1 cell differentiation, and decreased severity of Listeria monocytogenes infection. Mechanistically, HDAC6 directly deacetylated CBP-catalyzed acetylation of signal transducer and activator of transcription 4 (STAT4)-lysine (K) 667 via its enzymatic activity. Acetylation of STAT4-K667 is required for JAK2-mediated phosphorylation and activation of STAT4. Stat4K667R mutant mice lost the ability to normally differentiate into Th1 cells and developed severe Listeria infection. Our study identifies acetylation of STAT4-K667 as an essential signaling event for Th1 cell differentiation and defense against intracellular pathogen infections, and highlights the therapeutic potential of HDAC6 inhibitors for controlling intracellular pathogen infections.
Assuntos
Listeria monocytogenes , Listeriose , Camundongos , Animais , Acetilação , Células Th1 , Fator de Transcrição STAT4 , Transdução de Sinais , Diferenciação CelularRESUMO
Ten-eleven translocation (TET) proteins, the dioxygenase for DNA hydroxymethylation, are important players in nervous system development and diseases. However, their role in myelination and remyelination after injury remains elusive. Here, we identify a genome-wide and locus-specific DNA hydroxymethylation landscape shift during differentiation of oligodendrocyte-progenitor cells (OPC). Ablation of Tet1 results in stage-dependent defects in oligodendrocyte (OL) development and myelination in the mouse brain. The mice lacking Tet1 in the oligodendrocyte lineage develop behavioral deficiency. We also show that TET1 is required for remyelination in adulthood. Transcriptomic, genomic occupancy, and 5-hydroxymethylcytosine (5hmC) profiling reveal a critical TET1-regulated epigenetic program for oligodendrocyte differentiation that includes genes associated with myelination, cell division, and calcium transport. Tet1-deficient OPCs exhibit reduced calcium activity, increasing calcium activity rescues the differentiation defects in vitro. Deletion of a TET1-5hmC target gene, Itpr2, impairs the onset of OPC differentiation. Together, our results suggest that stage-specific TET1-mediated epigenetic programming and intracellular signaling are important for proper myelination and remyelination in mice.
Assuntos
Encéfalo/metabolismo , Proteínas de Ligação a DNA/metabolismo , DNA/metabolismo , Camundongos Mutantes Neurológicos/metabolismo , Proteínas Proto-Oncogênicas/metabolismo , Remielinização/fisiologia , 5-Metilcitosina/análogos & derivados , Animais , Ciclo Celular , Diferenciação Celular , Metilação de DNA , Proteínas de Ligação a DNA/genética , Genoma , Camundongos , Camundongos Knockout , Oligodendroglia/metabolismo , Organogênese , Proteínas Proto-Oncogênicas/genéticaRESUMO
T helper 17 (Th17)-cell differentiation triggered by interleukin-6 (IL-6) via STAT3 activation promotes inflammation in inflammatory bowel disease (IBD) patients. However, leukemia inhibitory factor (LIF), an IL-6 family cytokine, restricts inflammation by blocking Th17-cell differentiation via an unknown mechanism. Here, we report that microbiota dysregulation promotes LIF secretion by intestinal epithelial cells (IECs) in a mouse colitis model. LIF greatly activates STAT4 phosphorylation on multiple SPXX elements within the C-terminal transcription regulation domain. STAT4 and STAT3 act reciprocally on both canonical cis-inducible elements (SIEs) and noncanonical "AGG" elements at different loci. In lamina propria lymphocytes (LPLs), STAT4 activation by LIF blocks STAT3-dependent Il17a/Il17f promoter activation, whereas in IECs, LIF bypasses the extraordinarily low level of STAT4 to induce YAP gene expression via STAT3 activation. In addition, we found that the administration of LIF is sufficient to restore microbiome homeostasis. Thus, LIF effectively inhibits Th17 accumulation and promotes repair of damaged intestinal epithelium in inflamed colon, serves as a potential therapy for IBD.
Assuntos
Colite/prevenção & controle , Regulação da Expressão Gênica/efeitos dos fármacos , Inflamação/prevenção & controle , Mucosa Intestinal/efeitos dos fármacos , Fator Inibidor de Leucemia/farmacologia , Fator de Transcrição STAT3/metabolismo , Fator de Transcrição STAT4/fisiologia , Animais , Células Cultivadas , Colite/induzido quimicamente , Colite/imunologia , Inflamação/induzido quimicamente , Inflamação/imunologia , Interleucina-17/imunologia , Mucosa Intestinal/imunologia , Mucosa Intestinal/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Fosforilação , Fator de Transcrição STAT3/genética , Transdução de Sinais , Células Th17/imunologiaRESUMO
In mammalian cells, histone deacetylase (HDAC) and Sirtuin (SIRT) are two families responsible for removing acetyl groups from acetylated proteins. Here, we describe protein deacetylation coupled with deacetylimination as a function of lysyl oxidase (LOX) family members. LOX-like 3 (Loxl3) associates with Stat3 in the nucleus to deacetylate and deacetyliminate Stat3 on multiple acetyl-lysine sites. Surprisingly, Loxl3 N-terminal scavenger receptor cysteine-rich (SRCR) repeats, rather than the C-terminal oxidase catalytic domain, represent the major deacetylase/deacetyliminase activity. Loxl3-mediated deacetylation/deacetylimination disrupts Stat3 dimerization, abolishes Stat3 transcription activity, and restricts cell proliferation. In Loxl3-/- mice, Stat3 is constitutively acetylated and naive CD4+ T cells are potentiated in Th17/Treg cell differentiation. When overexpressed, the SRCR repeats from other LOX family members can catalyze protein deacetylation/deacetylimination. Thus, our findings delineate a hitherto-unknown mechanism of protein deacetylation and deacetylimination catalyzed by lysyl oxidases.
Assuntos
Aminoácido Oxirredutases/metabolismo , Linfócitos T CD4-Positivos/enzimologia , Colite/enzimologia , Processamento de Proteína Pós-Traducional , Fator de Transcrição STAT3/metabolismo , Acetilação , Aminoácido Oxirredutases/deficiência , Aminoácido Oxirredutases/genética , Animais , Linfócitos T CD4-Positivos/imunologia , Catálise , Diferenciação Celular , Núcleo Celular/enzimologia , Proliferação de Células , Colite/genética , Colite/imunologia , Modelos Animais de Doenças , Genótipo , Células HEK293 , Células HeLa , Humanos , Células MCF-7 , Camundongos Endogâmicos C57BL , Camundongos Knockout , Fenótipo , Domínios Proteicos , Multimerização Proteica , Interferência de RNA , Fator de Transcrição STAT3/genética , Linfócitos T Reguladores/enzimologia , Linfócitos T Reguladores/imunologia , Células Th17/enzimologia , Células Th17/imunologia , Transcrição Gênica , TransfecçãoRESUMO
Dmrt1 (Dsx- and Mab3-related transcription factor-1), a conserved transcription factor in different phyla, is a key regulator in sex determination. Here, we report the novel ncRNA gene Dmr (Dmrt1-related gene), from mouse chromosome 5 that trans-splices with Dmrt1 from chromosome 19 to generate a Dmrt1 protein that lacks the C-terminus. Dmr is mouse and rat specific, and the surrounding genes are also conserved in both species. Dmr is alternatively spliced, and three isoforms, Dmr a, b and c, are detected in the testis. Further, Dmr serves mainly as a 3' UTR, promotes trans-splicing and down-regulates the Dmrt1 protein. These results suggest that Dmr might play a negative regulatory role for Dmrt1 in male sexual development.