Table7_Pseudoautosomal Region 1 Overdosage Affects the Global Transcriptome in iPSCs From Patients With Klinefelter Syndrome and High-Grade X Chromosome Aneuploidies.xlsx

Klinefelter syndrome (KS) is the most prevalent aneuploidy in males and is characterized by a 47,XXY karyotype. Less frequently, higher grade sex chromosome aneuploidies (HGAs) can also occur. Here, using a paradigmatic cohort of KS and HGA induced pluripotent stem cells (iPSCs) carrying 49,XXXXY, 48,XXXY, and 47,XXY karyotypes, we identified the genes within the pseudoautosomal region 1 (PAR1) as the most susceptible to dosage-dependent transcriptional dysregulation and therefore potentially responsible for the progressively worsening phenotype in higher grade X aneuploidies. By contrast, the biallelically expressed non-PAR escape genes displayed high interclonal and interpatient variability in iPSCs and differentiated derivatives, suggesting that these genes could be associated with variable KS traits. By interrogating KS and HGA iPSCs at the single-cell resolution we showed that PAR1 and non-PAR escape genes are not only resilient to the X-inactive specific transcript (XIST)-mediated inactivation but also that their transcriptional regulation is disjointed from the absolute XIST expression level. Finally, we explored the transcriptional effects of X chromosome overdosage on autosomes and identified the nuclear respiratory factor 1 (NRF1) as a key regulator of the zinc finger protein X-linked (ZFX). Our study provides the first evidence of an X-dosage-sensitive autosomal transcription factor regulating an X-linked gene in low- and high-grade X aneuploidies.

克莱因费尔特综合征（KS）是男性中最常见的非整倍体，其特征为47,XXY的核型。较少见的情形为高级别性染色体非整倍体（HGAs）的发生。在本研究中，我们采用了一组典型的KS和HGA诱导的多能干细胞（iPSCs）群体，这些细胞携带49,XXXXY、48,XXXY和47,XXY的核型。通过这一研究，我们确定了伪常染色体区域1（PAR1）内的基因最易受剂量依赖性转录失调的影响，因此可能为高级别X非整倍体中逐渐恶化的表型负责。相比之下，双等位基因表达的PAR1逃逸基因在iPSCs及其分化产物中表现出高克隆间和患者间的变异性，表明这些基因可能与KS的变异性相关。通过在单细胞分辨率下对KS和HGA iPSCs进行探究，我们发现PAR1和PAR1逃逸基因不仅对X沉默特异性转录子（XIST）介导的失活具有抵抗力，而且它们的转录调控与XIST表达水平无关。最终，我们探讨了X染色体过表达对常染色体的转录效应，并确定了核呼吸因子1（NRF1）为锌指蛋白X连锁（ZFX）的关键调节因子。本研究首次提供了X剂量敏感的常染色体转录因子调节X连锁基因在低级和高级X非整倍体中的证据。