RESUMEN
Mammalian gametogenesis involves dramatic and tightly regulated chromatin remodeling, whose regulatory pathways remain largely unexplored. Here, we generate a comprehensive high-resolution structural and functional atlas of mouse spermatogenesis by combining in situ chromosome conformation capture sequencing (Hi-C), RNA sequencing (RNA-seq), and chromatin immunoprecipitation sequencing (ChIP-seq) of CCCTC-binding factor (CTCF) and meiotic cohesins, coupled with confocal and super-resolution microscopy. Spermatogonia presents well-defined compartment patterns and topological domains. However, chromosome occupancy and compartmentalization are highly re-arranged during prophase I, with cohesins bound to active promoters in DNA loops out of the chromosomal axes. Compartment patterns re-emerge in round spermatids, where cohesin occupancy correlates with transcriptional activity of key developmental genes. The compact sperm genome contains compartments with actively transcribed genes but no fine-scale topological domains, concomitant with the presence of protamines. Overall, we demonstrate how genome-wide cohesin occupancy and transcriptional activity is associated with three-dimensional (3D) remodeling during spermatogenesis, ultimately reprogramming the genome for the next generation.
Asunto(s)
Proteínas de Ciclo Celular/metabolismo , Proteínas Cromosómicas no Histona/metabolismo , Genómica/métodos , Espermatogénesis/genética , Humanos , Masculino , Conformación Molecular , CohesinasRESUMEN
Conventional G-banding cytogenetics (CC) detects chromosome 17 (chr17) abnormalities in 2% of patients with de novo myelodysplastic syndromes (MDS). We used CC and fluorescence in situ hybridization (FISH) (LSI p53/17p13.1) to assess deletion of 17p in 531 patients with de novo MDS from the Spanish Group of Hematological Cytogenetics. FISH detected - 17 or 17p abnormalities in 13 cases (2.6%) in whom no 17p abnormalities were revealed by CC: 0.9% of patients with a normal karyotype, 0% in non-informative cytogenetics, 50% of patients with a chr17 abnormality without loss of 17p and 4.7% of cases with an abnormal karyotype not involving chr17. Our results suggest that applying FISH of 17p13 to identify the number of copies of the TP53 gene could be beneficial in patients with a complex karyotype. We recommend using FISH of 17p13 in young patients with a normal karyotype or non-informative cytogenetics, and always in isolated del(17p).
Asunto(s)
Deleción Cromosómica , Cromosomas Humanos Par 17 , Hibridación Fluorescente in Situ , Síndromes Mielodisplásicos/genética , Proteína p53 Supresora de Tumor/genética , Bandeo Cromosómico , HumanosRESUMEN
The Shoc2 protein has been implicated in the positive regulation of the Ras-ERK pathway by increasing the functional binding interaction between Ras and Raf, leading to increased ERK activity. Here we found that Shoc2 overexpression induced sustained ERK phosphorylation, notably in the case of EGF stimulation, and Shoc2 knockdown inhibited ERK activation. We demonstrate that ectopic overexpression of human Shoc2 in PC12 cells significantly promotes neurite extension in the presence of EGF, a stimulus that induces proliferation rather than differentiation in these cells. Finally, Shoc2 depletion reduces both NGF-induced neurite outgrowth and ERK activation in PC12 cells. Our data indicate that Shoc2 is essential to modulate the Ras-ERK signaling outcome in cell differentiation processes involved in neurite outgrowth.
Asunto(s)
Factor de Crecimiento Epidérmico/metabolismo , Quinasas MAP Reguladas por Señal Extracelular/metabolismo , Péptidos y Proteínas de Señalización Intracelular/genética , Neuritas/metabolismo , Animales , Línea Celular Tumoral , Activación Enzimática/genética , Células HEK293 , Humanos , Péptidos y Proteínas de Señalización Intracelular/biosíntesis , Sistema de Señalización de MAP Quinasas , Células PC12 , Fosforilación , Interferencia de ARN , ARN Interferente Pequeño , Ratas , Proteínas ras/genética , Proteínas ras/metabolismoRESUMEN
The prognosis of chromosome 17 (chr17) abnormalities in patients with primary myelodysplastic syndrome (MDS) remains unclear. The revised International Prognostic Scoring System (IPSS-R) includes these abnormalities within the intermediate cytogenetic risk group. This study assessed the impact on overall survival (OS) and risk of acute myeloid leukemia transformation (AMLt) of chr17 abnormalities in 88 patients with primary MDS. We have compared this group with 1346 patients with primary MDS and abnormal karyotype without chr17 involved. The alterations of chr17 should be considered within group of poor prognosis. The different types of alterations of chromosome 17 behave different prognosis. The study confirms the intermediate prognostic impact of the i(17q), as stated in IPSS-R. The results of the study, however, provide valuable new information on the prognostic impact of alterations of chromosome 17 in complex karyotypes.