Abstract
To investigate X-chromosome inactivation (XCI) in human trophoblasts during early pregnancy, tropho-blast genomic DNA was extracted and analyzed for a Bst XI restriction endonuclease site polymorphism in the X-linked phosphoglycerate kinase gene, after digestion with methylation-sensitive Hpa II (control samples were digested instead with Afa I). Six villous trophoblast DNA samples were informative for the polymorphism (ie, heterozygous) and were derived from women homozygous for the polymorphism. These samples were then evaluated for XCI. In five of the six samples with Hpa II predigestion, the sizes of the two heterozygous band peaks differed; maternal X-chromosome (XM)-derived alleles showed smaller peak sizes than paternal X-chromosome (XP)-derived alleles, but the differences varied in degree. In samples obtained by microdissection from formalin-fixed, paraffin-embedded tissues (30 samples from different anchoring villi, and 38 samples from different branch villi), monoclonal band patterns of XP-derived alleles were observed more frequently than those of XM-derived alleles, but almost half of the samples showed polyclonal pat-terns. Our results suggest that a skewing of XCI exists in the human trophoblast; however, the degree of non-randomness due to predominant XP inactivation appears to be restricted. It is probable that transcription of the X inactivation center (XIC) begins earlier in mice than in humans.
Similar content being viewed by others
Article PDF
Author information
Authors and Affiliations
Additional information
Received: October 14, 1999 / Accepted: December 3, 1999
Rights and permissions
About this article
Cite this article
Uehara, S., Tamura, M., Nata, M. et al. X-chromosome inactivation in the human trophoblast of early pregnancy. J Hum Genet 45, 119–126 (2000). https://doi.org/10.1007/s100380050197
Published:
Issue Date:
DOI: https://doi.org/10.1007/s100380050197
This article is cited by
-
Examining Sex Differences in the Human Placental Transcriptome During the First Fetal Androgen Peak
Reproductive Sciences (2021)
-
Sex differences in the late first trimester human placenta transcriptome
Biology of Sex Differences (2018)
-
May anomalous X chromosome methylation be responsible for the spontaneous abortion of a male foetus?
Journal of Genetics (2008)
-
Twin study of genetic and aging effects on X chromosome inactivation
European Journal of Human Genetics (2005)
-
Skewed X Inactivation of the Normal Allele in Fully Mutated Female Carriers Determines the Levels of FMRP in Blood and the Fragile X Phenotype
Molecular Diagnosis (2005)