Parenting Stress in Immigrant Families of Children With an Autism Spectrum Disorder: A Comparison With Families From the Host Culture

Immigrant families of children with autism spectrum disorders (ASD) face significant challenges in accessing and using rehabilitation services appropriate for their child’s disorder. Compared to families native to their host country, the stress experienced by these families in relation to their child’s condition may be magnified by their immigrant status. This study compared self-reported parenting stress levels among 24 mothers and 17 fathers who had immigrated to Canada to income-matched, Canadian-born parents. Overall, Canadian-born parents tended to report higher stress levels than immigrant parents, but this may be primarily due to the high stress levels among Canadian-born fathers relative to immigrant fathers and mothers from both types of families. These findings highlight the necessity of using supplemental and specialized stress measures when focusing on immigrant families, for whom stress associated with the immigration process may compound or manifest separately from parenting stress. Cultural influences on the perception of ASD (its causes, treatment, and prognosis), children’s place in the family, and parents’ roles in childrearing may also impact stress

Formation of stress-specific p53 binding patterns is influenced by chromatin but not by modulation of p53 binding affinity to response elements†

The p53 protein is crucial for adapting programs of gene expression in response to stress. Recently, we revealed that this occurs partly through the formation of stress-specific p53 binding patterns. However, the mechanisms that generate these binding patterns remain largely unknown. It is not established whether the selective binding of p53 is achieved through modulation of its binding affinity to certain response elements (REs) or via a chromatin-dependent mechanism. To shed light on this issue, we used a microsphere assay for protein–DNA binding to measure p53 binding patterns on naked DNA. In parallel, we measured p53 binding patterns within chromatin using chromatin immunoprecipitation and DNase I coupled to ligation-mediated polymerase chain reaction footprinting. Through this experimental approach, we revealed that UVB and Nutlin-3 doses, which lead to different cellular outcomes, induce similar p53 binding patterns on naked DNA. Conversely, the same treatments lead to stress-specific p53 binding patterns on chromatin. We show further that altering chromatin remodeling using an histone acetyltransferase inhibitor reduces p53 binding to REs. Altogether, our results reveal that the formation of p53 binding patterns is not due to the modulation of sequence-specific p53 binding affinity. Rather, we propose that chromatin and chromatin remodeling are required in this process

Human single-nucleotide polymorphisms alter p53 sequence-specific binding at gene regulatory elements

p53 coordinates the expression of an intricate network of genes in response to stress signals. Sequence-specific DNA binding is essential for p53-mediated tumor suppression. We evaluated the impact of single-nucleotide polymorphisms (SNPs) in p53 response elements (p53RE) on DNA binding and gene expression in response to DNA damage. Using a bioinformatics approach based on incorporating p53 binding strength into a position weight matrix, we selected 32 SNPs in putative and validated p53REs. The microsphere assay for protein–DNA binding (MAPD) and allele-specific expression analysis was employed to assess the impact of SNPs on p53-DNA binding and gene expression, respectively. Comparing activated p53 binding in nuclear extracts from doxorubicin- or ionizing radiation (IR)-treated human cells, we observed little difference in binding profiles. Significant p53 binding was observed for most polymorphic REs and several displayed binding comparable to the p21 RE. SNP alleles predicted to lower p53 binding indeed reduced binding in 25 of the 32 sequences. Chromatin immunoprecipitation-sequencing in lymphoblastoid cells confirmed p53 binding to seven polymorphic p53 REs in response to doxorubicin. In addition, five polymorphisms were associated with altered gene expression following doxorubicin treatment. Our findings demonstrate an effective strategy to identify and evaluate SNPs that may alter p53-mediated stress responses

Lysine120 Interactions with p53 Response Elements can Allosterically Direct p53 Organization

p53 can serve as a paradigm in studies aiming to figure out how allosteric perturbations in transcription factors (TFs) triggered by small changes in DNA response element (RE) sequences, can spell selectivity in co-factor recruitment. p53-REs are 20-base pair (bp) DNA segments specifying diverse functions. They may be located near the transcription start sites or thousands of bps away in the genome. Their number has been estimated to be in the thousands, and they all share a common motif. A key question is then how does the p53 protein recognize a particular p53-RE sequence among all the similar ones? Here, representative p53-REs regulating diverse functions including cell cycle arrest, DNA repair, and apoptosis were simulated in explicit solvent. Among the major interactions between p53 and its REs involving Lys120, Arg280 and Arg248, the bps interacting with Lys120 vary while the interacting partners of other residues are less so. We observe that each p53-RE quarter site sequence has a unique pattern of interactions with p53 Lys120. The allosteric, DNA sequence-induced conformational and dynamic changes of the altered Lys120 interactions are amplified by the perturbation of other p53-DNA interactions. The combined subtle RE sequence-specific allosteric effects propagate in the p53 and in the DNA. The resulting amplified allosteric effects far away are reflected in changes in the overall p53 organization and in the p53 surface topology and residue fluctuations which play key roles in selective co-factor recruitment. As such, these observations suggest how similar p53-RE sequences can spell the preferred co-factor binding, which is the key to the selective gene transactivation and consequently different functional effects

Test fonctionnel de mesure des activités enzymatiques de réparation de l'ADN par excision resynthèse sur support miniaturisé : mise au point et applications

DNA repair is a very important cellular mechanism involved in various genetic diseases and in carcinogenesis. DNA repair systems exhibit complementarities and interactions recently highlighted. However, this complexity is not taken into account by functional assays available nowadays.Therefore we have designed a miniaturized in vitro assay allowing specific, functional and parallelized measurement of DNA repair activities. This test is an adaptation of an excision resynthesis assay to the microarray format.We first setup and optimized the microarray fabrication, the data analysis and normalization, and the repair reaction. We then validated the assay and demonstrated that DNA repair activities measured were specific. Finally we demonstrated the potential of the assay in two different domains. We first phenotyped different cell types: the results showed the similarity of human fibroblasts repair profiles, and also the different repair abilities existing between fibroblast, keratinocyte, and peripheral blood mononuclear cells. Moreover we studied adaptation of cells to gamma irradiation. We demonstrated that DNA repair activities are involved in the radio-adaptation of cells .Potential applications of this assay could be important in fundamental research as in applied one such as molecular screening, and in diagnosis.La réparation de l'ADN est un processus cellulaire très important comme le montre son implication dans de nombreuses maladies génétiques et la carcinogenèse. Les mécanismes des différents systèmes de réparation présentent des interactions et des complémentarités. Les tests fonctionnels utilisés jusqu'alors pour étudier les activités de réparation ne prennent pas en compte toute cette complexité.Nous avons développé un test in vitro offrant une mesure parallélisée, fonctionnelle et spécifique d'activités enzymatiques de réparation de l'ADN. Pour ce faire, nous avons adapté un test d'excision resynthèse au format biopuce.Nous avons mis au point les différentes étapes du test : la fabrication de la biopuce, la normalisation et l'analyse des données, les conditions de réactions biologiques. Nous avons ensuite validé le test en démontrant que nous mesurions des activités enzymatiques de réparation. Enfin deux expériences applicatives de ce test ont été réalisées. Nous avons tout d'abord mis en évidence la similitude des profils de réparation de trois souches de fibroblastes humains issus de cultures primaires, mais aussi les différences des capacités de réparation qu'il existe entre les fibroblastes, kératinocytes, et cellules mononuclées du sang périphérique. Par la suite, nous avons démontré que la réparation de l'ADN est impliquée dans la réponse adaptative des cellules au rayonnement ionisant. Les applications futures de ce test sont importantes, tant en recherche fondamentale qu'appliquée pour le criblage de molécules, ou encore dans le domaine diagnostic

Test fonctionnel de mesure des activités enzymatiques de réparation de l'ADN par excision resynthèse sur support miniaturisé : mise au point et applications

DNA repair is a very important cellular mechanism involved in various genetic diseases and in carcinogenesis. DNA repair systems exhibit complementarities and interactions recently highlighted. However, this complexity is not taken into account by functional assays available nowadays.Therefore we have designed a miniaturized in vitro assay allowing specific, functional and parallelized measurement of DNA repair activities. This test is an adaptation of an excision resynthesis assay to the microarray format.We first setup and optimized the microarray fabrication, the data analysis and normalization, and the repair reaction. We then validated the assay and demonstrated that DNA repair activities measured were specific. Finally we demonstrated the potential of the assay in two different domains. We first phenotyped different cell types: the results showed the similarity of human fibroblasts repair profiles, and also the different repair abilities existing between fibroblast, keratinocyte, and peripheral blood mononuclear cells. Moreover we studied adaptation of cells to gamma irradiation. We demonstrated that DNA repair activities are involved in the radio-adaptation of cells .Potential applications of this assay could be important in fundamental research as in applied one such as molecular screening, and in diagnosis.La réparation de l'ADN est un processus cellulaire très important comme le montre son implication dans de nombreuses maladies génétiques et la carcinogenèse. Les mécanismes des différents systèmes de réparation présentent des interactions et des complémentarités. Les tests fonctionnels utilisés jusqu'alors pour étudier les activités de réparation ne prennent pas en compte toute cette complexité.Nous avons développé un test in vitro offrant une mesure parallélisée, fonctionnelle et spécifique d'activités enzymatiques de réparation de l'ADN. Pour ce faire, nous avons adapté un test d'excision resynthèse au format biopuce.Nous avons mis au point les différentes étapes du test : la fabrication de la biopuce, la normalisation et l'analyse des données, les conditions de réactions biologiques. Nous avons ensuite validé le test en démontrant que nous mesurions des activités enzymatiques de réparation. Enfin deux expériences applicatives de ce test ont été réalisées. Nous avons tout d'abord mis en évidence la similitude des profils de réparation de trois souches de fibroblastes humains issus de cultures primaires, mais aussi les différences des capacités de réparation qu'il existe entre les fibroblastes, kératinocytes, et cellules mononuclées du sang périphérique. Par la suite, nous avons démontré que la réparation de l'ADN est impliquée dans la réponse adaptative des cellules au rayonnement ionisant. Les applications futures de ce test sont importantes, tant en recherche fondamentale qu'appliquée pour le criblage de molécules, ou encore dans le domaine diagnostic

High-resolution 4C reveals rapid p53-dependent chromatin reorganization of the CDKN1A locus in response to stress

A regulatory program involving hundreds of genes is coordinated by p53 to prevent carcinogenesis in response to stress. Given the importance of chromatin loops in gene regulation, we investigated whether DNA interactions participate in the p53 stress response. To shed light on this issue, we measured the binding dynamics of cohesin in response to stress. We reveal that cohesin is remodeled at specific loci during the stress response and that its binding within genes negatively correlates with transcription. At p53 target genes, stressinduced eviction of cohesin from gene bodies is concomitant to spatial reorganization of loci through the disruption of functional chromatin loops. These findings demonstrate that chromatin loops can be remodeled upon stress and contribute to the p53-driven stress response. Additionally, we also propose a mechanism whereby transcription-coupled eviction of cohesin from CDKN1A might act as a molecular switch to control spatial interactions between regulatory elements

Immigrant Families’ Perception of the Causes, First Manifestations, and Treatment of Autism Spectrum Disorder

Compared to families from their host country, families from immigrant backgrounds who have a child with autism spectrum disorder (ASD) tend to experience greater difficulties in accessing, using, and complying with intervention services for their child. This disparity may be partially accounted for by cultural differences in how families perceive the causes and symptoms of ASD as well as their treatment priorities. The present study sought to document these perceptions in immigrant families living in a Canadian city. Forty-five parents from Latin America, Africa, Western and Eastern Europe, the Caribbean, East Asia, and the Middle East participated in a semi-structured interview. These data were examined qualitatively through thematic analysis to first document all parents’ perceptions, then to contrast mothers’ and fathers’ responses, and finally to examine common themes as a function of country of origin. The most frequently mentioned causes of ASD were environmental factors such as vaccines and diet. Moreover, some participants did not know the cause of their child’s ASD. The majority of parents cited the absence of speech as one of the first symptoms noted in their child. Priorities for intervention varied: mothers tended to prioritize speech therapy, whereas fathers favored support in school. Taken as a whole, these findings highlight the need to implement informational programs for these families. </p

Quality of Life in Immigrant Parents of Children With Autism Spectrum Disorder: A Comparison With Parents From the Host Culture

Objectives: Studies conducted on families of children with autism spectrum disorder (ASD) indicate that the period following the child’s diagnosis can be challenging, especially for immigrant families. Indeed, they tend to have additional difficulties in accessing and using ASD diagnosis and early intervention services. To date, few studies have contrasted the experiences of immigrant and native families. Method: During the period following their child’s ASD diagnosis, 104 immigrant and Canadian-born mothers and fathers completed the Beach Center FQOL Scale and provided ratings of perceived support. Results: Immigrant families were less satisfied with their FQOL than Canadian-born parents, but no gender differences were observed. However, gender and immigration-status related patterns emerged with respect to the relative importance and satisfaction levels across dimensions of FQOL. Additionally, fewer immigrant families reported having access to external support, a predictor of FQOL, than Canadian families. Conclusion: Although no statistically significant gender differences emerged, patterns in the data suggest that each parent may benefit from different services. Overall, these findings highlight the importance of developing programs that take into account parents’ gender and cultural background and provide means of developing external support networks.</p