Changes in chromosome number impair fitness by disrupting the balance of gene expression. Here we analyze mechanisms to compensate for changes in gene dose that accompanied the evolution of sex chromosomes from autosomes. Using single-copy transgenes integrated throughout the genome, we show that expression of all X-linked transgenes is balanced between XX hermaphrodites and XO males. However, proximity of a dosage compensation complex (DCC) binding site ( site) is neither necessary to repress X-linked transgenes nor sufficient to repress transgenes on autosomes. Thus, X is broadly permissive for dosage compensation, and the DCC acts via a chromosome-wide mechanism to balance transcription between sexes. In contrast, no analogous X-chromosome-wide mechanism balances transcription between X and autosomes: expression of compensated hermaphrodite X-linked transgenes is half that of autosomal transgenes. Furthermore, our results argue against an X-chromosome dosage compensation model contingent upon -directed positioning of X relative to the nuclear periphery.
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http://dx.doi.org/10.7554/eLife.17365 | DOI Listing |
Sci Rep
January 2025
Department of Chromosome Biomedical Engineering, School of Life Science, Faculty of Medicine, Tottori University, 86 Nishi-cho, Yonago, Tottori, 683‑8503, Japan.
Duchenne muscular dystrophy (DMD) is an X-linked recessive disorder caused by mutations of the dystrophin gene, which spans 2.4 Mb on the X chromosome. Creatine kinase (CK) activity in blood and titin fragment levels in urine have been identified as biomarkers in DMD to monitor disease progression and evaluate therapeutic intervention.
View Article and Find Full Text PDFThromb Haemost
December 2024
Pharmacology, Chulalongkorn University, Bangkok, Thailand.
Wiskott-Aldrich syndrome (WAS) is a severe X-linked disorder caused by loss-of-function mutations in the WAS gene, responsible for encoding WASP, a key regulator of actin cytoskeleton in all hematopoietic cells except red blood cells. The mechanism underlying microthrombocytopenia, a distinctive feature of WAS and a major contributor to mortality, remains not fully elucidated. In this study, using different gene editing strategies, we corrected mutations in patient-derived WAS-induced pluripotent stem cell lines, generating isogeneic WAS iPSC lines.
View Article and Find Full Text PDFHaemophilia
December 2024
Investigative Toxicology, Takeda Development Center of the Americas, Cambridge, USA.
Introduction: Haemophilia A is an X-linked bleeding disorder resulting from a deficiency of factor VIII (FVIII). To date, multiple gene therapies have entered clinical trials with the goal of providing durable haemostatic protection from a single dose. TAK 754 (BAX 888) is an investigational AAV8-based gene therapy containing a FVIII transgene.
View Article and Find Full Text PDFMol Ther Methods Clin Dev
December 2024
uniQure biopharma B.V., Amsterdam 1105 BP, the Netherlands.
We developed a novel adeno-associated virus 5 gene therapy (AAV5-GLA) expressing human alpha-galactosidase A (GLA) under the control of a novel, small and strong, liver-restricted promoter. We assessed the preclinical potential of AAV5-GLA for treating Fabry disease, an X-linked hereditary metabolic disorder resulting from mutations in the gene encoding GLA that lead to accumulation of the substrates globotriaosylceramide and globotriaosylsphingosine, causing heart, kidney, and central nervous system dysfunction. Effects of intravenously administered AAV5-GLA were evaluated in (1) GLA-knockout mice aged 7-8 weeks (early in disease) and 20 weeks (nociception phenotype manifestation) and (2) cynomolgus macaques during an 8-week period.
View Article and Find Full Text PDFNat Neurosci
January 2025
HuidaGene Therapeutics Inc., Shanghai, China.
Duplication of methyl-CpG-binding protein 2 (MECP2) gene causes MECP2 duplication syndrome (MDS). To normalize the duplicated MECP2 in MDS, we developed a high-fidelity Cas13Y (hfCas13Y) system capable of targeting the MECP2 (hfCas13Y-gMECP2) messenger RNA for degradation and reducing protein levels in the brain of humanized MECP2 transgenic mice. Moreover, the intracerebroventricular adeno-associated virus (AAV) delivery of hfCas13Y-gMECP2 in newborn or adult MDS mice restored dysregulated gene expression and improved behavior deficits.
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