Alternative Lengthening of Telomeres is characterized by reduced compaction of telomeric chromatin

摘要: Proper telomeric chromatin configuration is thought to be essential for telomere homeostasis and stability. Previous studies in mouse suggested that loss of heterochromatin marks at telomeres might favor onset Alternative Lengthening Telomeres (ALT) pathway, by promoting homologous recombination. However, analysis status human ALT has never been reported. Here, using isogenic cell lines cellular hybrids, which rely either on telomerase or maintain telomeres, we show compaction reduced this associated with a global decrease H3K9me3. This, subsequently, leads upregulation transcription. Accordingly, restoration more condensed through telomerase-dependent elongation short reduces We further ATRX remodeler function, frequent characteristic cells, not sufficient condensation nor increase the expression RNA species. These results offer new insight properties cells support hypothesis decondensation important pathway.