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A Tth111I RFLP in intron 1 of the mouse Pgk-1 gene allows tracing of X chromosome inactivation

Journal Article · · American Journal of Human Genetics
OSTI ID:133802
;  [1]
  1. Emory Univ. School of Medicine, Atlanta, GA (United States)
The X-linked immunodeficiency (xid) in CBA/N mice serves as a model for the X-linked agammaglobulinemia (XLA) syndrome in humans. Like the XLA carriers, the female mice heterozygous for xid (X{sup xid}/X{sup W}) are asymptomatic. The pattern of X chromosome inactivation in the F1 heterozygotes [CBA/N (X{sup xid}/X{sup xid}) X CAST/Ei (X{sup W}/Y)] was investigated by monitoring the methylation status of the two Pgk-1 alleles. Methylation of a CpG dinucleotide in the 5{prime} region of the Pgk-1 gene was previously shown to absolutely correlate with the inactivation of the corresponding X chromosome. In order to distinguish the two alleles, the proximal end of intron 1 of the Pgk-1 gene from CBA/N and CAST/Ei was sequenced. Several nucleotide polymorphisms, including a Tth111I RFLP, were detected in close proximity of the critical CpG dinucleotide. This allowed us to devise an assay based on PCR-amplification of a target DNA encompassing the CpG site as well as the Tth111I site. Results indicate that in circulating B lymphocytes of the female heterozygote only the X-chromosome carrying the normal allele is active (non-random inactivation of the X chromosome) whereas in non-B cells both the X chromosomes are active (random inactivation of the X chromosome). These results were further confirmed by direct measurement of transcription of the two alleles (X{sup xid} and X{sup W}).
OSTI ID:
133802
Report Number(s):
CONF-941009--
Journal Information:
American Journal of Human Genetics, Journal Name: American Journal of Human Genetics Journal Issue: Suppl.3 Vol. 55; ISSN AJHGAG; ISSN 0002-9297
Country of Publication:
United States
Language:
English