Localization of the X inactivation centre on the human X chromosome in Xq13.
X-chromosome inactivation results in the strictly cis-limited inactivation of many but not all genes on one of the two X chromosomes during early development in somatic cells of mammalian females. One feature of virtually all models of X inactivation is the existence of an X-inactivation centre (XIC) required in cis for inactivation to occur. This concept predicts that all structurally abnormal X chromosomes capable of being inactivated have in common a defineable region of the X chromosome. Here we report an analysis of several such rearranged human X chromosomes and define a minimal region of overlap. The results are consistent with models invoking a single XIC and provide a molecular foothold for cloning and analysing the XIC region. One of the markers that defines this region is the XIST gene, which is expressed specifically from inactive, but not active, X chromosomes. The localization of the XIST gene to the XIC region on the human X chromosome implicates XIST in some aspect of X inactivation.
Brown
C J
CJ
Department of Genetics, Stanford University School of Medicine, California 94305.
Lafreniere
R G
RG
Powers
V E
VE
Sebastio
G
G
Ballabio
A
A
Pettigrew
A L
AL
Ledbetter
D H
DH
Levy
E
E
Craig
I W
IW
Willard
H F
HF
D002874:Chromosome Mapping; D004303:Dosage Compensation, Genetic; D015321:Gene Rearrangement; D006801:Humans; D014960:X Chromosome / Q000648:ultrastructure*