RESUMO
Prospermatogonia (ProSpg) link the embryonic development of male primordial germ cells to the healthy establishment of postnatal spermatogonia and spermatogonial stem cells. While these spermatogenic precursor cells undergo the characteristic transitions of cycling and quiescence, the transcriptional events underlying these developmental hallmarks remain unknown. Here, we investigated the expression and function of TBP-associated factor 4b (Taf4b) in the timely development of quiescent mouse ProSpg using an integration of gene expression profiling and chromatin mapping. We find that Taf4b mRNA expression is elevated during the transition of mitotic-to-quiescent ProSpg and Taf4b-deficient ProSpg are delayed in their entry into quiescence. Gene ontology, protein network analysis, and chromatin mapping demonstrate that TAF4b is a direct and indirect regulator of chromatin and cell cycle-related gene expression programs during ProSpg quiescence. Further validation of these cell cycle mRNA changes due to the loss of TAF4b was accomplished via immunostaining for proliferating cell nuclear antigen (PCNA). Together, these data indicate that TAF4b is a key transcriptional regulator of the chromatin and quiescent state of the developing mammalian spermatogenic precursor lineage.
RESUMO
Establishment of a healthy ovarian reserve is contingent upon numerous regulatory pathways during embryogenesis. Previously, mice lacking TBP-associated factor 4b (Taf4b) were shown to exhibit a diminished ovarian reserve. However, potential oocyte-intrinsic functions of TAF4b have not been examined. Here, we use a combination of gene expression profiling and chromatin mapping to characterize TAF4b-dependent gene regulatory networks in mouse oocytes. We find that Taf4b-deficient oocytes display inappropriate expression of meiotic, chromatin modification/organization, and X-linked genes. Furthermore, dysregulated genes in Taf4b-deficient oocytes exhibit an unexpected amount of overlap with dysregulated genes in oocytes from XO female mice, a mouse model of Turner Syndrome. Using Cleavage Under Targets and Release Using Nuclease (CUT&RUN), we observed TAF4b enrichment at genes involved in chromatin remodeling and DNA repair, some of which are differentially expressed in Taf4b-deficient oocytes. Interestingly, TAF4b target genes were enriched for Sp/Klf family and NFY target motifs rather than TATA-box motifs, suggesting an alternative mode of promoter interaction. Together, our data connect several gene regulatory nodes that contribute to the precise development of the mammalian ovarian reserve.
Assuntos
Redes Reguladoras de Genes/genética , Oogênese , Fatores Associados à Proteína de Ligação a TATA/genética , Fator de Transcrição TFIID/genética , Animais , Reparo do DNA , Embrião de Mamíferos/citologia , Embrião de Mamíferos/metabolismo , Feminino , Células Germinativas/citologia , Células Germinativas/metabolismo , Meiose , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Oócitos/citologia , Oócitos/metabolismo , Regiões Promotoras Genéticas , Fatores Associados à Proteína de Ligação a TATA/deficiência , Fatores Associados à Proteína de Ligação a TATA/metabolismo , Fator de Transcrição TFIID/deficiência , Fator de Transcrição TFIID/metabolismo , Cromossomo X/genética , Cromossomo X/metabolismoRESUMO
A key knowledge gap blocking development of effective therapeutics for Alzheimer's disease (AD) is the lack of understanding of how amyloid beta (Aß) peptide and pathological forms of the tau protein cooperate in causing disease phenotypes. Within a mouse tau-deficient background, we probed the molecular, cellular, and behavioral disruption triggered by the influence of wild-type human tau on human Aß-induced pathology. We find that Aß and tau work cooperatively to cause a hyperactivity behavioral phenotype and to cause downregulation of transcription of genes involved in synaptic function. In both our mouse model and human postmortem tissue, we observe accumulation of pathological tau in synapses, supporting the potential importance of synaptic tau. Importantly, tau reduction in the mice initiated after behavioral deficits emerge corrects behavioral deficits, reduces synaptic tau levels, and substantially reverses transcriptional perturbations, suggesting that lowering synaptic tau levels may be beneficial in AD.
Assuntos
Doença de Alzheimer/metabolismo , Peptídeos beta-Amiloides/metabolismo , Proteínas tau/metabolismo , Idoso , Idoso de 80 Anos ou mais , Doença de Alzheimer/patologia , Animais , Feminino , Humanos , Masculino , Camundongos , Microglia/metabolismo , Comportamento Espacial , Sinapses/metabolismo , TranscriptomaRESUMO
NAB1 and 2 are coregulators for early growth response (Egr) transcription factors. The NAB1 nuclear localization signal (NLS) was previously described as a bipartite NLS of sequence R(X2 )K(X11 )KRXK. The sequence is conserved in NAB2 as K(X2 )R(X11 )KKXK; however, whether it functions as the NAB2 NLS has not been tested. We show that the KKXK motif in NAB2 is necessary and sufficient to mediate nuclear localization. Mutation of the KKXK motif to AAXA causes cytoplasmic localization of NAB2, while Lys/Arg-to-Ala mutations of the upstream K(X2 )R motif have no effect. Fusion of the KKXK motif to cytoplasmic protein eIF2Bε causes nuclear localization. Altogether, this study refines our knowledge of the NAB2 NLS, demonstrating that KKXK343-346 is necessary and sufficient for nuclear localization.
Assuntos
Núcleo Celular/metabolismo , Fatores de Transcrição de Resposta de Crescimento Precoce/metabolismo , Proteínas de Neoplasias/química , Proteínas de Neoplasias/metabolismo , Proteínas Repressoras/química , Proteínas Repressoras/metabolismo , Motivos de Aminoácidos , Animais , Linhagem Celular , Citoplasma/metabolismo , Fator de Iniciação 2B em Eucariotos/metabolismo , Humanos , Camundongos , Mutação , Proteínas de Neoplasias/genética , Sinais de Localização Nuclear , Proteínas Repressoras/genéticaRESUMO
Pica is a life-threatening behavior displayed by many individuals with developmental disabilities. In the current study, automatic reinforcement maintained the pica of 3 participants. Following functional analyses of pica, response-effort manipulations were conducted in which the effort to obtain pica or alternative items was varied systematically. Several general relations emerged as a result of the study. First, levels of pica were reduced relative to baseline when alternative items were available independent of the effort required to obtain alternative items or pica. Second, increasing the effort for alternative items resulted in increases in pica relative to when effort for alternative items was low. Third, increasing response effort for pica produced reductions in pica relative to baseline when alternative items were unavailable. Fourth, the highest levels of pica occurred when the effort to engage in pica was low or medium and no alternative items were available. These findings are discussed in terms of the relative effects of quality of reinforcement and response effort on behavior.