RESUMO
The neurodevelopmental disorders Prader-Willi syndrome (PWS) and Schaaf-Yang syndrome (SYS) both arise from genomic alterations within human chromosome 15q11-q13. A deletion of the SNORD116 cluster, encoding small nucleolar RNAs, or frameshift mutations within MAGEL2 result in closely related phenotypes in individuals with PWS or SYS, respectively. By investigation of their subcellular localization, we observed that in contrast to a predominant cytoplasmic localization of wild-type (WT) MAGEL2, a truncated MAGEL2 mutant was evenly distributed between the cytoplasm and the nucleus. To elucidate regulatory pathways that may underlie both diseases, we identified protein interaction partners for WT or mutant MAGEL2, in particular the survival motor neuron protein (SMN), involved in spinal muscular atrophy, and the fragile-X-messenger ribonucleoprotein (FMRP), involved in autism spectrum disorders. The interactome of the non-coding RNA SNORD116 was also investigated by RNA-CoIP. We show that WT and truncated MAGEL2 were both involved in RNA metabolism, while regulation of transcription was mainly observed for WT MAGEL2. Hence, we investigated the influence of MAGEL2 mutations on the expression of genes from the PWS locus, including the SNORD116 cluster. Thereby, we provide evidence for MAGEL2 mutants decreasing the expression of SNORD116, SNORD115, and SNORD109A, as well as protein-coding genes MKRN3 and SNRPN, thus bridging the gap between PWS and SYS.
Assuntos
Proteínas de Neoplasias , Síndrome de Prader-Willi , RNA Nucleolar Pequeno , Síndrome de Prader-Willi/genética , Humanos , RNA Nucleolar Pequeno/genética , Proteínas de Neoplasias/genética , Proteínas de Neoplasias/metabolismo , Proteínas/genética , Proteínas/metabolismo , Cromossomos Humanos Par 15/genética , Mutação , Células HEK293 , Citoplasma/metabolismo , Peptídeos e Proteínas de Sinalização Intracelular , Proteínas Intrinsicamente DesordenadasRESUMO
Ehlers-Danlos syndrome (EDS) belongs to a spectrum of rare heritable connective tissue disorders and is characterised by hyperextensibility, joint hypermobility and tissue fragility. Peripheral blood mononuclear cells (PBMCs) from a vascular EDS (vEDS) patient, known as the rarest EDS subtype, carrying a heterozygous nonsense mutation c.430C > T (p.Q105*) in the COL3A1 gene, which is essential for type III collagen synthesis, were reprogrammed into induced pluripotent stem cells (iPSCs). The generated iPSCs exhibit high expression of pluripotency-associated markers, possess trilineage differentiation capacity and reveal a normal karyotype. This novel patient-specific cell line enables in-depth pathophysiological studies of vEDS.
Assuntos
Síndrome de Ehlers-Danlos Tipo IV , Síndrome de Ehlers-Danlos , Células-Tronco Pluripotentes Induzidas , Humanos , Códon sem Sentido , Leucócitos Mononucleares , Mutação/genética , Síndrome de Ehlers-Danlos/genética , Colágeno Tipo III/genéticaRESUMO
Congenital hyperinsulinemic hypoglycemia (HH) is the most frequent cause of persistent and recurrent hypoglycemia. Peripheral mononuclear blood cells (PBMCs) from a patient diagnosed with HH, alongside autism-spectrum-disorder (ASD), carrying a heterozygous c.812 T>A (L271H) mutation in the voltage-gated calcium channel subunit Cav1.3-encoding gene CACNA1D, were reprogrammed into induced pluripotent stem cells (iPSC). The CACNA1D L271H iPSC (IBKMOLi002-A) exhibit a normal karyotype, high expression of pluripotency-associated markers and the capacity to differentiate into cells of all three germ layers. We provide a novel patient-specific iPSC line, allowing to study HH, ASD, the associated neurodevelopmental disorder as well as CACNA1D-associated channelopathies in general.