Human Genetics

, Volume 119, Issue 3, pp 267–275

Inactivation status of PCDH11X: sexual dimorphisms in gene expression levels in brain

  • Alexandra M. Lopes
  • Norman Ross
  • James Close
  • Adam Dagnall
  • António Amorim
  • Timothy J. Crow
Original Investigation

DOI: 10.1007/s00439-006-0134-0

Cite this article as:
Lopes, A.M., Ross, N., Close, J. et al. Hum Genet (2006) 119: 267. doi:10.1007/s00439-006-0134-0

Abstract

Genes escaping X-inactivation are predicted to contribute to differences in gene dosage between the sexes and are the prime candidates for being involved in the phenotype observed in individuals with X chromosome aneuploidies. Of particular interest is ProtocadherinX (PCDH11X or PCDHX), a recently described gene expressed in brain. In humans, PCDH11X has a homologue on the Y chromosome and is predicted to escape from X-inactivation. Employing bisulphite sequencing analysis we found absence of CpG island methylation on both the active and the inactive X chromosomes, providing a strong indication that PCDH11X escapes inactivation in humans. Furthermore, a sexual dimorphism in levels of expression in brain tissue was observed by quantitative real-time PCR, with females presenting an up to 2-fold excess in the abundance of PCDH11X transcripts. We relate these findings to sexually dimorphic traits in the human brain. Interestingly, PCDH11X/Y gene pair is unique to Homo sapiens, since the X-linked gene was transposed to the Y chromosome after the human–chimpanzee lineages split. Although no differences in promoter methylation were found between humans and chimpanzees, evidence of an upregulation of PCDH11X in humans deserves further investigation.

Supplementary material

439_2006_134_MOESM1_ESM.xls (18 kb)
Supplementary material

Copyright information

© Springer-Verlag 2006

Authors and Affiliations

  • Alexandra M. Lopes
    • 1
    • 2
  • Norman Ross
    • 3
  • James Close
    • 3
  • Adam Dagnall
    • 3
  • António Amorim
    • 1
    • 2
  • Timothy J. Crow
    • 3
  1. 1.IPATIMUP, Instituto de Patologia e Imunologia Molecular da Universidade do PortoPortoPortugal
  2. 2.Faculdade de CiênciasUniversidade do PortoPortoPortugal
  3. 3.Department of Psychiatry, POWIC SANE Research CentreUniversity of Oxford, Warneford HospitalOxfordUK