Differential expression of steroid sulphatase locus on active and inactive human X chromosome

Barbara R Migeon, Larry J. Shapiro, Robert A. Norum, Thuluvancheri Mohandas, Joyce Axelman, Rebecca L. Dabora

Research output: Contribution to journalArticle

Abstract

The X chromosome in mammalian somatic cells is subject to unique regulation - usually genes on a single X chromosome are expressed while those on other X chromosomes are inactivated1. The X-locus for steroid sulphatase (STS; EC 3.1.6.2), the microsomal enzyme that catalyses the hydrolysis of various 3β-hydroxysteroid sulphates, is exceptional because it seems to escape inactivation. Evidence for this comes from fibroblast clones in females heterozygous for mutations that result in a severe deficiency of this enzyme in affected males; all clones from these heterozygotes have STS activity, and enzyme-deficient clones that are expected if the locus were subject to inactivation2, have not been found3. Further evidence that the STS locus escapes inactivation is that the human inactive X chromosome contributes STS activity to mouse-human hybrid cells4. On the basis of these hybrid studies5,6 the STS locus has been mapped to the distal half of the short arm (p22-pter) of the human X chromosome. Although the STS locus on both X chromosomes in human female cells is expressed, quantitative measurements of STS activity in males and females do not accurately reflect the sex differences in number of X chromosomes7-13 (Table 1). The ratio of mean values for normal females to that of normal males is greater than 1:1 but less than the ratio of 2:1 expected if STS loci on all X chromosomes were equally expressed. The incomplete dosage effect suggests that the STS locus on the inactive X chromosome might not be fully expressed. To test this hypothesis, we examined two heterozygotes for X-linked STS deficiency who were also heterozygous for the common electrophoretic variants of glucose-6-phosphate dehydrogenase (G6PD A and B). Studies of fibroblast clones from these females provide evidence, presented here, for differential expression of STS loci on the active and inactive X chromosome.

Original languageEnglish (US)
Pages (from-to)838-840
Number of pages3
JournalNature
Volume299
Issue number5886
DOIs
StatePublished - 1982

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Steryl-Sulfatase
Chromosomes, Human, X
X Chromosome
Clone Cells
Heterozygote
Enzymes
Fibroblasts
Hydroxysteroids
Sex Characteristics
Sulfates
Reference Values
Hydrolysis
Mutation
Genes

ASJC Scopus subject areas

  • General

Cite this

Migeon, B. R., Shapiro, L. J., Norum, R. A., Mohandas, T., Axelman, J., & Dabora, R. L. (1982). Differential expression of steroid sulphatase locus on active and inactive human X chromosome. Nature, 299(5886), 838-840. https://doi.org/10.1038/299838a0

Differential expression of steroid sulphatase locus on active and inactive human X chromosome. / Migeon, Barbara R; Shapiro, Larry J.; Norum, Robert A.; Mohandas, Thuluvancheri; Axelman, Joyce; Dabora, Rebecca L.

In: Nature, Vol. 299, No. 5886, 1982, p. 838-840.

Research output: Contribution to journalArticle

Migeon, BR, Shapiro, LJ, Norum, RA, Mohandas, T, Axelman, J & Dabora, RL 1982, 'Differential expression of steroid sulphatase locus on active and inactive human X chromosome', Nature, vol. 299, no. 5886, pp. 838-840. https://doi.org/10.1038/299838a0
Migeon, Barbara R ; Shapiro, Larry J. ; Norum, Robert A. ; Mohandas, Thuluvancheri ; Axelman, Joyce ; Dabora, Rebecca L. / Differential expression of steroid sulphatase locus on active and inactive human X chromosome. In: Nature. 1982 ; Vol. 299, No. 5886. pp. 838-840.
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