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1.
Dev Sci ; : e13505, 2024 Mar 28.
Artigo em Inglês | MEDLINE | ID: mdl-38549194

RESUMO

Learning safe versus dangerous cues is crucial for survival. During development, parents can influence fear learning by buffering their children's stress response and increasing exploration of potentially aversive stimuli. Rodent findings suggest that these behavioral effects are mediated through parental presence modulation of the amygdala and medial prefrontal cortex (mPFC). Here, we investigated whether similar parental modulation of amygdala and mPFC during fear learning occurs in humans. Using a within-subjects design, behavioral (final N = 48, 6-17 years, mean = 11.61, SD = 2.84, 60% females/40% males) and neuroimaging data (final N = 39, 6-17 years, mean = 12.03, SD = 2.98, 59% females/41% males) were acquired during a classical fear conditioning task, which included a CS+ followed by an aversive noise (US; 75% reinforcement rate) and a CS-. Conditioning occurred once in physical contact with the participant's parent and once alone (order counterbalanced). Region of interest analyses examined the unconditioned stress response by BOLD activation to the US (vs. implicit baseline) and learning by activation to the CS+ (vs. CS-). Results showed that during US presentation, parental presence reduced the centromedial amygdala activity, suggesting buffering of the unconditioned stress response. In response to learned stimuli, parental presence reduced mPFC activity to the CS+ (relative to the CS-), although this result did not survive multiple comparisons' correction. These preliminary findings indicate that parents modulate amygdala and mPFC activity during exposure to unconditioned and conditioned fear stimuli, potentially providing insight into the neural mechanisms by which parents act as a social buffer during fear learning. RESEARCH HIGHLIGHTS: (1)This study used a within-participant experimental design to investigate how parental presence (vs. absence) affects youth's neural responses in a classical fear conditioning task. (2)Parental presence reduced the youth's centromedial amygdala activation to the unconditioned stimulus (US), suggesting parental buffering of the neural unconditioned response (UR). (3)Parental presence reduced the youth's mPFC activation to a conditioned threat cue (CS+) compared to a safety cue (CS-), suggesting possible parental modulation of fear learning.

2.
Dev Sci ; : e13518, 2024 Apr 25.
Artigo em Inglês | MEDLINE | ID: mdl-38664866

RESUMO

Cognitive science has demonstrated that we construct knowledge about the world by abstracting patterns from routinely encountered experiences and storing them as semantic memories. This preregistered study tested the hypothesis that caregiving-related early adversities (crEAs) shape affective semantic memories to reflect the content of those adverse interpersonal-affective experiences. We also tested the hypothesis that because affective semantic memories may continue to evolve in response to later-occurring positive experiences, child-perceived attachment security will inform their content. The sample comprised 160 children (ages 6-12 at Visit 1; 87F/73 M), 66% of whom experienced crEAs (n = 105). At Visit 1, crEA exposure prior to study enrollment was operationalized as parental-reports endorsing a history of crEAs (abuse/neglect, permanent/significant parent-child separation); while child-reports assessed concurrent attachment security. A false memory task was administered online ∼2.5 years later (Visit 2) to probe the content of affective semantic memories-specifically attachment schemas. Results showed that crEA exposure (vs. no exposure) was associated with a higher likelihood of falsely endorsing insecure (vs. secure) schema scenes. Attachment security moderated the association between crEA exposure and insecure schema-based false recognition. Findings suggest that interpersonal-affective semantic schemas include representations of parent-child interactions that may capture the quality of one's own attachment experiences and that these representations shape how children remember attachment-relevant narrative events. Findings are also consistent with the hypothesis that these affective semantic memories can be modified by later experiences. Moving forward, the approach taken in this study provides a means of operationalizing Bowlby's notion of internal working models within a cognitive neuroscience framework. RESEARCH HIGHLIGHTS: Affective semantic memories representing insecure schema knowledge (child needs + needs-not-met) may be more salient, elaborated, and persistent among youths exposed to early caregiving adversity. All youths, irrespective of early caregiving adversity exposure, may possess affective semantic memories that represent knowledge of secure schemas (child needs + needs-met). Establishing secure relationships with parents following early-occurring caregiving adversity may attenuate the expression of insecure semantic memories, suggesting potential malleability. Affective semantic memories include schema representations of parent-child interactions that may capture the quality of one's own attachment experiences and shape how youths remember attachment-relevant events.

3.
Pediatr Res ; 93(1): 253-259, 2023 01.
Artigo em Inglês | MEDLINE | ID: mdl-35444294

RESUMO

BACKGROUND: Studies have shown that infant temperament varies with maternal psychosocial factors, in utero illness, and environmental stressors. We predicted that the pandemic would shape infant temperament through maternal SARS-CoV-2 infection during pregnancy and/or maternal postnatal stress. To test this, we examined associations among infant temperament, maternal prenatal SARS-CoV-2 infection, maternal postnatal stress, and postnatal COVID-related life disruptions. METHODS: We tested 63 mother-infant dyads with prenatal maternal SARS-CoV-2 infections and a comparable group of 110 dyads without infections. To assess postnatal maternal stress, mothers completed the Perceived Stress Scale 4 months postpartum and an evaluation of COVID-related stress and life disruptions 6 months postpartum. Mothers reported on infant temperament when infants were 6-months-old using the Infant Behavior Questionnaire-Revised (IBQ-R) Very Short Form. RESULTS: Maternal SARS-CoV-2 infection during pregnancy was not associated with infant temperament or maternal postnatal stress. Mothers with higher self-reported postnatal stress rated their infants lower on the Positive Affectivity/Surgency and Orienting/Regulation IBQ-R subscales. Mothers who reported greater COVID-related life disruptions rated their infants higher on the Negative Emotionality IBQ-R subscale. CONCLUSIONS: Despite no effect of prenatal maternal SARS-CoV-2 infection, stress and life disruptions incurred by the COVID-19 pandemic were associated with infant temperament at 6-months. IMPACT: SARS-CoV-2 infection during pregnancy is not associated with postnatal ratings of COVID-related life disruptions, maternal stress, or infant temperament. Postnatal ratings of maternal stress during the COVID-19 pandemic are associated with normative variation in maternal report of infant temperament at 6 months of age. Higher postnatal ratings of maternal stress are associated with lower scores on infant Positive Affectivity/Surgency and Orienting/Regulation at 6 months of age. Higher postnatal ratings of COVID-related life disruptions are associated with higher scores on infant Negative Emotionality at 6 months of age.


Assuntos
COVID-19 , Temperamento , Feminino , Humanos , Lactente , Temperamento/fisiologia , Pandemias , SARS-CoV-2 , Mães/psicologia , Comportamento do Lactente/fisiologia , Comportamento do Lactente/psicologia
4.
Dev Psychopathol ; 34(2): 621-634, 2022 05.
Artigo em Inglês | MEDLINE | ID: mdl-35314012

RESUMO

Early psychosocial adversities exist at many levels, including caregiving-related, extrafamilial, and sociodemographic, which despite their high interrelatedness may have unique impacts on development. In this paper, we focus on caregiving-related early adversities (crEAs) and parse the heterogeneity of crEAs via data reduction techniques that identify experiential cooccurrences. Using network science, we characterized crEA cooccurrences to represent the comorbidity of crEA experiences across a sample of school-age children (n = 258; 6-12 years old) with a history of crEAs. crEA dimensions (variable level) and crEA subtypes (subject level) were identified using parallel factor analysis/principal component analysis and graph-based Louvain community detection. Bagging enhancement with cross-validation provided estimates of robustness. These data-driven dimensions/subtypes showed evidence of stability, transcended traditional sociolegally defined groups, were more homogenous than sociolegally defined groups, and reduced statistical correlations with sociodemographic factors. Finally, random forests showed both unique and common predictive importance of the crEA dimensions/subtypes for childhood mental health symptoms and academic skills. These data-driven outcomes provide additional tools and recommendations for crEA data reduction to inform precision medicine efforts in this area.


Assuntos
Transtornos Mentais , Saúde Mental , Criança , Humanos , Transtornos Mentais/epidemiologia , Comorbidade
5.
J Exp Child Psychol ; 221: 105461, 2022 09.
Artigo em Inglês | MEDLINE | ID: mdl-35617793

RESUMO

Adults quickly orient toward sources of danger and deploy fight-or-flight tactics to manage threatening situations. In contrast, infants who cannot implement the safety strategies available to adults and depend heavily on caregivers for survival are more likely to turn toward familiar adults, such as their parents, to help them navigate threatening circumstances. However, work has yet to investigate how readily children and adolescents orient toward their parents in threatening or fearful contexts. The current work addressed this question using a visual search paradigm that included arrays of parents' and strangers' faces as target and distractor stimuli, preceded by a fear or neutral emotional priming procedure. Linear mixed-effects models showed that children and adolescents (N = 88, age range = 4-17 years; 42M/46F) were faster to search for the face of their parent than of a stranger. However, fear priming attenuated this effect of the parent on search times, such that children and adolescents were significantly slower to orient toward their parent in an array of strangers' faces if they were first primed with fear as opposed to a neutral video. This work indicates that fear priming may phasically interfere with parental orienting during childhood and adolescence, possibly because fear reallocates attention away from parents and toward (potentially threatening) unfamiliar people in the environment to facilitate the development of independent threat learning and coping systems.


Assuntos
Expressão Facial , Medo , Adolescente , Adulto , Atenção , Criança , Pré-Escolar , Emoções , Medo/psicologia , Humanos , Lactente , Pais/psicologia
6.
Dev Sci ; 24(6): e13133, 2021 11.
Artigo em Inglês | MEDLINE | ID: mdl-34080760

RESUMO

Cognitive control is typically described as disrupted following exposure to early caregiving instability. While much of the work within this field has approached cognitive control broadly, evidence from adults retrospectively reporting early-life instability has shown more nuanced effects on cognitive control, even demonstrating enhancements in certain subdomains. That is, exposure to unstable caregiving may disrupt some areas of cognitive control, yet promote adaptation in others. Here, we investigated three domains of cognitive control in a sample of school-age children (N = 275, Age = 6-12 years) as a function of early caregiving instability, defined as the total number of caregiving switches. Results demonstrated that caregiving instability was associated with reduced response inhibition (Go/No-Go) and attentional control (Flanker), but enhanced cognitive flexibility (Dimensional Change Card Sort Task Switching). Conversely, there were no statistically significant associations with group (i.e., institutional care versus foster care) or maltreatment exposure and these patterns. These findings build on the specialization framework, suggesting that caregiving instability results in both decrements and enhancements in children's cognitive control, consistent with the hypothesis that cognitive control development is scaffolded by early environmental pressures.


Assuntos
Cognição , Cuidados no Lar de Adoção , Adulto , Controle Comportamental , Criança , Cognição/fisiologia , Humanos , Estudos Retrospectivos
7.
Dev Psychobiol ; 63(1): 16-30, 2021 01.
Artigo em Inglês | MEDLINE | ID: mdl-32671835

RESUMO

Young children rely heavily on their caregivers to gain information about the environment, especially during times of duress. Therefore, considering parental assessments of behavior in the context of stressful environments may better facilitate our understanding of the longstanding association between early environmental stressors and changes in child behavior and physiology. Confirming many previous reports, a higher degree of household stress exposure was associated with elevated mental health symptoms in 2- to 6-year-old children (N = 115; anxiety and externalizing behaviors), which were verified in a subset of children with laboratory-based behaviors (N = 46). However, these associations were mediated by parental anxiety symptoms, which were also associated with increased cortisol levels in children. A closer look at the stressors indicated that it was the adult-targeted, and not the child-targeted, stressors that correlated most with children's behavior problems. These results highlight the importance of considering the mediating effect of parents, when examining associations between household stress and young children's behavioral development.


Assuntos
Pais , Comportamento Problema , Adulto , Ansiedade , Transtornos de Ansiedade , Criança , Comportamento Infantil , Pré-Escolar , Humanos
8.
Dev Psychopathol ; 32(1): 309-328, 2020 02.
Artigo em Inglês | MEDLINE | ID: mdl-30919798

RESUMO

Gastrointestinal and mental disorders are highly comorbid, and animal models have shown that both can be caused by early adversity (e.g., parental deprivation). Interactions between the brain and bacteria that live within the gastrointestinal system (the microbiome) underlie adversity-gastrointestinal-anxiety interactions, but these links have not been investigated during human development. In this study, we utilized data from a population of 344 youth (3-18 years old) who were raised with their biological parents or were exposed to early adverse caregiving experiences (i.e., institutional or foster care followed by international adoption) to explore adversity-gastrointestinal-anxiety associations. In Study 1, we demonstrated that previous adverse care experiences were associated with increased incidence of gastrointestinal symptoms in youth. Gastrointestinal symptoms were also associated with concurrent and future anxiety (measured across 5 years), and those gastrointestinal symptoms mediated the adversity-anxiety association at Time 1. In a subsample of children who provided both stool samples and functional magnetic resonance imaging of the brain (Study 2, which was a "proof-of-principle"), adversity was associated with changes in diversity (both alpha and beta) of microbial communities, and bacteria levels (adversity-associated and adversity-independent) were correlated with prefrontal cortex activation to emotional faces. Implications of these data for supporting youth mental health are discussed.


Assuntos
Transtornos de Ansiedade/psicologia , Ansiedade/psicologia , Gastroenteropatias/psicologia , Saúde Mental , Adolescente , Afeto/fisiologia , Ansiedade/diagnóstico por imagem , Transtornos de Ansiedade/diagnóstico por imagem , Encéfalo/diagnóstico por imagem , Criança , Pré-Escolar , Feminino , Gastroenteropatias/diagnóstico por imagem , Humanos , Imageamento por Ressonância Magnética , Masculino
10.
bioRxiv ; 2023 Feb 18.
Artigo em Inglês | MEDLINE | ID: mdl-36824818

RESUMO

It has been established that early-life adversity impacts brain development, but the role of development itself has largely been ignored. We take a developmentally-sensitive approach to examine the neurodevelopmental sequelae of early adversity in a preregistered meta-analysis of 27,234 youth (birth to 18-years-old), providing the largest group of adversity-exposed youth to date. Findings demonstrate that early-life adversity does not have an ontogenetically uniform impact on brain volumes, but instead exhibits age-, experience-, and region-specific associations. Relative to non-exposed comparisons, interpersonal early adversity (e.g., family-based maltreatment) was associated with initially larger volumes in frontolimbic regions until ~10-years-old, after which these exposures were linked to increasingly smaller volumes. By contrast, socioeconomic disadvantage (e.g., poverty) was associated with smaller volumes in temporal-limbic regions in childhood, which were attenuated at older ages. These findings advance ongoing debates regarding why, when, and how early-life adversity shapes later neural outcomes.

11.
Neurosci Biobehav Rev ; 150: 105210, 2023 07.
Artigo em Inglês | MEDLINE | ID: mdl-37141961

RESUMO

It has been established that early-life adversity impacts brain development, but the role of development itself has largely been ignored. We take a developmentally-sensitive approach to examine the neurodevelopmental sequelae of early adversity in a preregistered meta-analysis of 27,234 youth (birth to 18-years-old), providing the largest group of adversity-exposed youth to date. Findings demonstrate that early-life adversity does not have an ontogenetically uniform impact on brain volumes, but instead exhibits age-, experience-, and region-specific associations. Relative to non-exposed comparisons, interpersonal early adversity (e.g., family-based maltreatment) was associated with initially larger volumes in frontolimbic regions until ∼10-years-old, after which these exposures were linked to increasingly smaller volumes. By contrast, socioeconomic disadvantage (e.g., poverty) was associated with smaller volumes in temporal-limbic regions in childhood, which were attenuated at older ages. These findings advance ongoing debates regarding why, when, and how early-life adversity shapes later neural outcomes.


Assuntos
Encéfalo , Disparidades Socioeconômicas em Saúde , Adolescente , Humanos , Criança , Pobreza , Estudos Longitudinais
12.
Biol Psychiatry Glob Open Sci ; 3(2): 169-178, 2023 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-37124361

RESUMO

Significant advances have been made in recent years regarding the developmental trajectories of brain circuits and networks, revealing links between brain structure and function. Emerging evidence highlights the importance of developmental trajectories in determining early psychiatric outcomes. However, efforts to encourage crosstalk between basic developmental neuroscience and clinical practice are limited. Here, we focus on the potential advantage of considering features of neural circuit development when optimizing treatments for adolescent patient populations. Drawing on characteristics of adolescent neurodevelopment, we highlight two examples, safety cues and incentives, that leverage insights from neural circuit development and may have great promise for augmenting existing behavioral treatments for anxiety disorders during adolescence. This commentary seeks to serve as a framework to maximize the translational potential of basic research in developmental populations for strengthening psychiatric treatments. In turn, input from clinical practice including the identification of age-specific clinically relevant phenotypes will continue to guide future basic research in the same neural circuits to better reflect clinical practices. Encouraging reciprocal communication to bridge the gap between basic developmental neuroscience research and clinical implementation is an important step toward advancing both research and practice in this domain.

13.
J Dev Orig Health Dis ; 14(5): 591-601, 2023 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-37732425

RESUMO

The deleterious effects of adversity are likely intergenerational, such that one generation's adverse experiences can affect the next. Epidemiological studies link maternal adversity to offspring depression and anxiety, possibly via transmission mechanisms that influence offspring fronto-limbic connectivity. However, studies have not thoroughly disassociated postnatal exposure effects nor considered the role of offspring sex. We utilized infant neuroimaging to test the hypothesis that maternal childhood maltreatment (CM) would be associated with increased fronto-limbic connectivity in infancy and tested brain-behavior associations in childhood. Ninety-two dyads participated (32 mothers with CM, 60 without; 52 infant females, 40 infant males). Women reported on their experiences of CM and non-sedated sleeping infants underwent MRIs at 2.44 ± 2.74 weeks. Brain volumes were estimated via structural MRI and white matter structural connectivity (fiber counts) via diffusion MRI with probabilistic tractography. A subset of parents (n = 36) reported on children's behaviors at age 5.17 ± 1.73 years. Males in the maltreatment group demonstrated greater intra-hemispheric fronto-limbic connectivity (b = 0.96, p= 0.008, [95%CI 0.25, 1.66]), no differences emerged for females. Fronto-limbic connectivity was related to somatic complaints in childhood only for males (r = 0.673, p = 0.006). Our findings suggest that CM could have intergenerational associations to offspring brain development, yet mechanistic studies are needed.


Assuntos
Substância Branca , Masculino , Lactente , Criança , Humanos , Feminino , Pré-Escolar , Substância Branca/diagnóstico por imagem , Mães , Encéfalo/diagnóstico por imagem , Imageamento por Ressonância Magnética , Ansiedade
14.
JAMA Pediatr ; 176(6): e215563, 2022 06 01.
Artigo em Inglês | MEDLINE | ID: mdl-34982107

RESUMO

Importance: Associations between in utero exposure to maternal SARS-CoV-2 infection and neurodevelopment are speculated, but currently unknown. Objective: To examine the associations between maternal SARS-CoV-2 infection during pregnancy, being born during the COVID-19 pandemic regardless of maternal SARS-CoV-2 status, and neurodevelopment at age 6 months. Design, Setting, and Participants: A cohort of infants exposed to maternal SARS-CoV-2 infection during pregnancy and unexposed controls was enrolled in the COVID-19 Mother Baby Outcomes Initiative at Columbia University Irving Medical Center in New York City. All women who delivered at Columbia University Irving Medical Center with a SARS-CoV-2 infection during pregnancy were approached. Women with unexposed infants were approached based on similar gestational age at birth, date of birth, sex, and mode of delivery. Neurodevelopment was assessed using the Ages & Stages Questionnaire, 3rd Edition (ASQ-3) at age 6 months. A historical cohort of infants born before the pandemic who had completed the 6-month ASQ-3 were included in secondary analyses. Exposures: Maternal SARS-CoV-2 infection during pregnancy and birth during the COVID-19 pandemic. Main Outcomes and Measures: Outcomes were scores on the 5 ASQ-3 subdomains, with the hypothesis that maternal SARS-CoV-2 infection during pregnancy would be associated with decrements in social and motor development at age 6 months. Results: Of 1706 women approached, 596 enrolled; 385 women were invited to a 6-month assessment, of whom 272 (70.6%) completed the ASQ-3. Data were available for 255 infants enrolled in the COVID-19 Mother Baby Outcomes Initiative (114 in utero exposed, 141 unexposed to SARS-CoV-2; median maternal age at delivery, 32.0 [IQR, 19.0-45.0] years). Data were also available from a historical cohort of 62 infants born before the pandemic. In utero exposure to maternal SARS-CoV-2 infection was not associated with significant differences on any ASQ-3 subdomain, regardless of infection timing or severity. However, compared with the historical cohort, infants born during the pandemic had significantly lower scores on gross motor (mean difference, -5.63; 95% CI, -8.75 to -2.51; F1,267 = 12.63; P<.005), fine motor (mean difference, -6.61; 95% CI, -10.00 to -3.21; F1,267 = 14.71; P < .005), and personal-social (mean difference, -3.71; 95% CI, -6.61 to -0.82; F1,267 = 6.37; P<.05) subdomains in fully adjusted models. Conclusions and Relevance: In this study, birth during the pandemic, but not in utero exposure to maternal SARS-CoV-2 infection, was associated with differences in neurodevelopment at age 6 months. These early findings support the need for long-term monitoring of children born during the COVID-19 pandemic.


Assuntos
COVID-19 , Complicações Infecciosas na Gravidez , COVID-19/epidemiologia , Criança , Feminino , Humanos , Lactente , Recém-Nascido , Cidade de Nova Iorque/epidemiologia , Pandemias , Gravidez , Complicações Infecciosas na Gravidez/epidemiologia , SARS-CoV-2
15.
J Cell Biol ; 167(6): 1075-85, 2004 Dec 20.
Artigo em Inglês | MEDLINE | ID: mdl-15611333

RESUMO

CFTRDeltaF508 exhibits a correctable protein-folding defect that leads to its misfolding and premature degradation, which is the cause of cystic fibrosis (CF). Herein we report on the characterization of the CFTRDeltaF508 biogenic intermediate that is selected for proteasomal degradation and identification of cellular components that polyubiquitinate CFTRDeltaF508. Nonubiquitinated CFTRDeltaF508 accumulates in a kinetically trapped, but folding competent conformation, that is maintained in a soluble state by cytosolic Hsc70. Ubiquitination of Hsc70-bound CFTRDeltaF508 requires CHIP, a U box containing cytosolic cochaperone. CHIP is demonstrated to function as a scaffold that nucleates the formation of a multisubunit E3 ubiquitin ligase whose reconstituted activity toward CFTR is dependent upon Hdj2, Hsc70, and the E2 UbcH5a. Inactivation of the Hsc70-CHIP E3 leads CFTRDeltaF508 to accumulate in a nonaggregated state, which upon lowering of cell growth temperatures, can fold and reach the cell surface. Inhibition of CFTRDeltaF508 ubiquitination can increase its cell surface expression and may provide an approach to treat CF.


Assuntos
Regulador de Condutância Transmembrana em Fibrose Cística/metabolismo , Regulador de Condutância Transmembrana em Fibrose Cística/farmacologia , Proteínas de Choque Térmico HSP70/metabolismo , Chaperonas Moleculares/metabolismo , Dobramento de Proteína , Ubiquitina-Proteína Ligases/antagonistas & inibidores , Animais , Células COS , Linhagem Celular , Chlorocebus aethiops , Regulador de Condutância Transmembrana em Fibrose Cística/genética , Retículo Endoplasmático/metabolismo , Regulação da Expressão Gênica , Proteínas de Choque Térmico HSC70 , Humanos , Proteínas de Ligação ao Ferro/genética , Proteínas de Ligação ao Ferro/metabolismo , Enzimas de Conjugação de Ubiquitina/genética , Enzimas de Conjugação de Ubiquitina/metabolismo , Ubiquitina-Proteína Ligases/metabolismo
16.
Arch Biochem Biophys ; 401(2): 271-6, 2002 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-12054478

RESUMO

The human cyclin Bl gene is cell cycle regulated with maximal activity during G(2)/M. We examined the role of histone deacetylation in cyclin Bl regulation using the histone deacetylase inhibitor trichostatin A (TSA). TSA treatment (100 ng/ml) of NIH3T3 cells containing the luciferase reporter construct pCycB(-287)-LUC caused an increase in promoter activity in G(0) and G(1) but no significant change in G(2). Removal of upstream sequences including an E-box and Sp1 site eliminated the TSA induced increase in G(0) and G(1), and caused a decrease in promoter activity during S and G(2). Promoter activity increased only 2-fold following TSA treatment of G(0) cells containing the construct pCycB(MUT-E-Box)-LUC with an E-box mutation, and a decrease in activity was detected during G(2). We conclude that histone deacetylation contributes to the repression of cyclin B1 expression in G(0) and G(1), and that this mechanism requires, in part, the E-box. TSA reduction of cyclin B1 promoter activity in G(2), however, involves sequences within the first 119 bp. A working model for cyclin B1 regulation is provided.


Assuntos
Ciclo Celular/efeitos dos fármacos , Ciclo Celular/genética , Ciclina B/genética , Ácidos Hidroxâmicos/farmacologia , Células 3T3 , Acetilação , Animais , Ciclina B1 , Inibidores Enzimáticos/farmacologia , Fase G1/efeitos dos fármacos , Fase G1/genética , Fase G2/efeitos dos fármacos , Fase G2/genética , Genes Reguladores/efeitos dos fármacos , Inibidores de Histona Desacetilases , Histonas/química , Histonas/metabolismo , Humanos , Camundongos , Modelos Biológicos , Mutação , Regiões Promotoras Genéticas/efeitos dos fármacos , Fase de Repouso do Ciclo Celular/efeitos dos fármacos , Fase de Repouso do Ciclo Celular/genética , Fase S/efeitos dos fármacos , Fase S/genética , Regulação para Cima/efeitos dos fármacos
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