A new structure for the murine Xist gene and its relationship to chromosome choice/counting during X-chromosome inactivation
- Harvard Institute of Human Genetics, Harvard Medical School and Beth Israel Deaconess Medical Center, Boston, MA 02115
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Edited by Thomas W. Cline, University of California, Berkeley, CA, and approved April 21, 1999 (received for review February 17, 1999)
Abstract
In this report, we present structural data for the murine Xist gene. The data presented in this paper demonstrate that the murine Xist transcript is at least 17.4 kb, not 14.3 kb as previously reported. The new structure of the murine Xist gene described herein has seven exons, not six. Exon VII encodes an additional 3.1 kb of information at the 3′ end. Exon VII contains seven possible sites for polyadenylation; four of these sites are located in the newly discovered 3′ end. Consequently, it is possible that several distinct transcripts may be produced through differential polyadenylation of a primary transcript. Alternative use of polyadenylation signals could result in size changes for exon VII. Two major species of Xist are detectable by Northern analysis, consistent with differential polyadenylation. In this paper, we propose a model for the role of the Xist 3′ end in the process of X-chromosome counting and choice during embryonic development.
Footnotes
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↵ * To whom reprint requests should be addressed. e-mail: wstrauss{at}hihg.med.harvard.edu.
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This paper was submitted directly (Track II) to the Proceedings Office.
- ABBREVIATIONS:
- EST,
- expressed sequence tag;
- FISH,
- fluorescence in situ hybridization
- Copyright © 1999, The National Academy of Sciences
