• We are sorry, but NCBI web applications do not support your browser and may not function properly. More information
Logo of pnasPNASInfo for AuthorsSubscriptionsAboutThis Article
Proc Natl Acad Sci U S A. May 1985; 82(10): 3390–3394.
PMCID: PMC397781

Incomplete X chromosome dosage compensation in chorionic villi of human placenta.

Abstract

Studies of glucose-6-phosphate dehydrogenase (G6PD) in heterozygous cells from chorionic villi of five fetal and one newborn placenta show that the locus on the allocyclic X is expressed in many cells of this trophectoderm derivative. Heterodimers were present in clonal populations of cells with normal diploid karyotype and a late replicating X chromosome. The expression of the two X chromosomes was unequal, based on ratios of homodimers and heterodimers in clones. Studies of DNA, digested with Hpa II and probed with cloned genomic G6PD sequences, indicate that expression of the locus in chorionic villi is associated with hypomethylation of 3' CpG clusters. These findings suggest that dosage compensation, at least at the G6PD locus, has not been well established or maintained (or both) in placental tissue. Furthermore, the active X chromosome in these human cells of trophoblastic origin can be either the paternal or maternal one; therefore, paternal X inactivation in extraembryonic lineages is not an essential feature of mammalian X dosage compensation.

Full text

Full text is available as a scanned copy of the original print version. Get a printable copy (PDF file) of the complete article (1.1M), or click on a page image below to browse page by page. Links to PubMed are also available for Selected References.

Images in this article

Selected References

These references are in PubMed. This may not be the complete list of references from this article.
  • Lyon MF. X-chromosome inactivation and developmental patterns in mammals. Biol Rev Camb Philos Soc. 1972 Jan;47(1):1–35. [PubMed]
  • Migeon BR. Stability of X chromosomal inactivation in human somatic cells. Nature. 1972 Sep 8;239(5367):87–89. [PubMed]
  • Migeon BR, Wolf SF, Mareni C, Axelman J. Derepression with decreased expression of the G6PD locus on the inactive X chromosome in normal human cells. Cell. 1982 Jun;29(2):595–600. [PubMed]
  • Razin A, Riggs AD. DNA methylation and gene function. Science. 1980 Nov 7;210(4470):604–610. [PubMed]
  • Sager R, Kitchin R. Selective silencing of eukaryotic DNA. Science. 1975 Aug 8;189(4201):426–433. [PubMed]
  • Holliday R, Pugh JE. DNA modification mechanisms and gene activity during development. Science. 1975 Jan 24;187(4173):226–232. [PubMed]
  • Mohandas T, Sparkes RS, Shapiro LJ. Reactivation of an inactive human X chromosome: evidence for X inactivation by DNA methylation. Science. 1981 Jan 23;211(4480):393–396. [PubMed]
  • Toniolo D, D'Urso M, Martini G, Persico M, Tufano V, Battistuzzi G, Luzzatto L. Specific methylation pattern at the 3' end of the human housekeeping gene for glucose 6-phosphate dehydrogenase. EMBO J. 1984 Sep;3(9):1987–1995. [PMC free article] [PubMed]
  • Wolf SF, Jolly DJ, Lunnen KD, Friedmann T, Migeon BR. Methylation of the hypoxanthine phosphoribosyltransferase locus on the human X chromosome: implications for X-chromosome inactivation. Proc Natl Acad Sci U S A. 1984 May;81(9):2806–2810. [PMC free article] [PubMed]
  • Yen PH, Patel P, Chinault AC, Mohandas T, Shapiro LJ. Differential methylation of hypoxanthine phosphoribosyltransferase genes on active and inactive human X chromosomes. Proc Natl Acad Sci U S A. 1984 Mar;81(6):1759–1763. [PMC free article] [PubMed]
  • Schmidt M, Stolzmann WM, Baranovskaya LI. Replication variants of the human inactive X chromosome. I. Variability within lymphocytes of single individuals. Chromosoma. 1982;85(3):405–412. [PubMed]
  • Hunt PA, Jacobs PA. In vitro growth and chromosome constitution of placental cells. I. Spontaneous and elective abortions. Cytogenet Cell Genet. 1985;39(1):1–6. [PubMed]
  • Wolf SF, Migeon BR. Clusters of CpG dinucleotides implicated by nuclease hypersensitivity as control elements of housekeeping genes. Nature. 1985 Apr 4;314(6010):467–469. [PubMed]
  • Migeon BR, Do TT. In search of non-random X inactivation: studies of fetal membranes heterozygous for glucose-6-phosphate dehydrogenase. Am J Hum Genet. 1979 Sep;31(5):581–585. [PMC free article] [PubMed]
  • Takagi N, Sasaki M. Preferential inactivation of the paternally derived X chromosome in the extraembryonic membranes of the mouse. Nature. 1975 Aug 21;256(5519):640–642. [PubMed]
  • Harper MI, Fosten M, Monk M. Preferential paternal X inactivation in extraembryonic tissues of early mouse embryos. J Embryol Exp Morphol. 1982 Feb;67:127–135. [PubMed]
  • Kratzer PG, Chapman VM, Lambert H, Evans RE, Liskay RM. Differences in the DNA of the inactive X chromosomes of fetal and extraembryonic tissues of mice. Cell. 1983 May;33(1):37–42. [PubMed]
  • Migeon BR, Sprenkle JA, Do TT. Stability of the "two active X" phenotype in triploid somatic cells. Cell. 1979 Nov;18(3):637–641. [PubMed]
  • Corsaro CM, Migeon BR. Gene expression in euploid human hybrid cells: ouabain resistance is codominant. Somatic Cell Genet. 1978 Sep;4(5):531–540. [PubMed]
  • Monk M, Harper MI. Sequential X chromosome inactivation coupled with cellular differentiation in early mouse embryos. Nature. 1979 Sep 27;281(5729):311–313. [PubMed]
  • van der Ploeg LH, Flavell RA. DNA methylation in the human gamma delta beta-globin locus in erythroid and nonerythroid tissues. Cell. 1980 Apr;19(4):947–958. [PubMed]
  • Chapman V, Forrester L, Sanford J, Hastie N, Rossant J. Cell lineage-specific undermethylation of mouse repetitive DNA. Nature. 1984 Jan 19;307(5948):284–286. [PubMed]

Articles from Proceedings of the National Academy of Sciences of the United States of America are provided here courtesy of National Academy of Sciences

Formats:

Related citations in PubMed

See reviews...See all...

Cited by other articles in PMC

See all...

Links

  • Cited in Books
    Cited in Books
    PubMed Central articles cited in books
  • MedGen
    MedGen
    Related information in MedGen
  • PubMed
    PubMed
    PubMed citations for these articles
  • Substance
    Substance
    PubChem Substance links

Recent Activity

Your browsing activity is empty.

Activity recording is turned off.

Turn recording back on

See more...