Human Embryonic Stem Cells Do Not Change Their X Inactivation Status during Differentiation

Publication date: Available online 16 December 2016
Source:Cell Reports
Author(s): Sanjeet Patel, Giancarlo Bonora, Anna Sahakyan, Rachel Kim, Constantinos Chronis, Justin Langerman, Sorel Fitz-Gibbon, Liudmilla Rubbi, Rhys J.P. Skelton, Reza Ardehali, Matteo Pellegrini, William E. Lowry, Amander T. Clark, Kathrin Plath
Applications of embryonic stem cells (ESCs) require faithful chromatin changes during differentiation, but the fate of the X chromosome state in differentiating ESCs is unclear. Female human ESC lines either carry two active X chromosomes (XaXa), an Xa and inactive X chromosome with or without XIST RNA coating (Xi^XIST+Xa;XiXa), or an Xa and an eroded Xi (XeXa) where the Xi no longer expresses XIST RNA and has partially reactivated. Here, we established XiXa, XeXa, and XaXa ESC lines and followed their X chromosome state during differentiation. Surprisingly, we found that the X state pre-existing in primed ESCs is maintained in differentiated cells. Consequently, differentiated XeXa and XaXa cells lacked XIST, did not induce X inactivation, and displayed higher X-linked gene expression than XiXa cells. These results demonstrate that X chromosome dosage compensation is not required for ESC differentiation. Our data imply that Xi^XIST+Xa ESCs are most suited for downstream applications and show that all other X states are abnormal byproducts of our ESC derivation and propagation method.

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Teaser

The fate of the X chromosome in cells differentiated from female human embryonic stem cell (hESC) lines remains controversial. Patel et al. analyze the X chromosome state of numerous hESC lines during derivation, propagation, and differentiation. They establish a hierarchy of X states in hESCs and find that the X chromosome state pre-existing in hESCs is maintained during differentiation.


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