Student Author(s)

Christine Clemson

GSBS Program

Cell Biology

UMMS Affiliation

Department of Cell Biology

Date

7-14-1998

Document Type

Article

Medical Subject Headings

Animals; Cell Line; Cell Nucleus; *Dosage Compensation, Genetic; Humans; Hybrid Cells; In Situ Hybridization, Fluorescence; Mice; RNA, Messenger; *RNA, Untranslated; Transcription Factors; X Chromosome

Disciplines

Cell Biology | Life Sciences | Medicine and Health Sciences

Abstract

These studies address whether XIST RNA is properly localized to the X chromosome in somatic cells where human XIST expression is reactivated, but fails to result in X inactivation (Tinker, A.V., and C.J. Brown. 1998. Nucl. Acids Res. 26:2935-2940). Despite a nuclear RNA accumulation of normal abundance and stability, XIST RNA does not localize in reactivants or in naturally inactive human X chromosomes in mouse/ human hybrid cells. The XIST transcripts are fully stabilized despite their inability to localize, and hence XIST RNA localization can be uncoupled from stabilization, indicating that these are separate steps controlled by distinct mechanisms. Mouse Xist RNA tightly localized to an active X chromosome, demonstrating for the first time that the active X chromosome in somatic cells is competent to associate with Xist RNA. These results imply that species-specific factors, present even in mature, somatic cells that do not normally express Xist, are necessary for localization. When Xist RNA is properly localized to an active mouse X chromosome, X inactivation does not result. Therefore, there is not a strict correlation between Xist localization and chromatin inactivation. Moreover, expression, stabilization, and localization of Xist RNA are not sufficient for X inactivation. We hypothesize that chromosomal association of XIST RNA may initiate subsequent developmental events required to enact transcriptional silencing.

Rights and Permissions

Citation: J Cell Biol. 1998 Jul 13;142(1):13-23. Link to article on publisher's website

Related Resources

Link to article in PubMed

PubMed ID

9660859