Abstract
Quiescent lymphocytes have small nuclei, filled with masses of facultative heterochromatin. Upon receiving mitogenic signals, these cells undergo nuclear enlargement, chromatin decondensation, the reactivation of cell proliferation, and changes in the intranuclear positioning of key genes. We examined the levels and intranuclear localization of major histone modifications and non-histone heterochromatin proteins in quiescent and reactivated mouse spleen lymphocytes. Dramatic and selective changes in localization of two heterochromatin-associated proteins, the histone variant macroH2A and HP1alpha occurred during lymphocyte reactivation. Reciprocal changes in the locations of these two proteins were observed in activated lymphocytes and cultured mouse fibroblasts induced into quiescence. We also describe a new apocentric nuclear compartment with a unique set of histone modifications that occurs as a zone of chromatin surrounding centromeric heterochromatin in differentiated lymphocytes. It is within this zone that the most significant changes occur in the transition from proliferation to quiescence. Our results suggest that constitutive centromeric heterochromatin plays an active role in cell differentiation and reactivation.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
