Human Genetics

, Volume 99, Issue 2, pp 262–265

Localisation of a human homologue of the Drosophila mnb and rat Dyrk genes to chromosome 21q22.2

  • Haiming Chen
  • Stylianos E. Antonarakis
Original investigation

DOI: 10.1007/s004390050350

Cite this article as:
Chen, H. & Antonarakis, S. Hum Genet (1997) 99: 262. doi:10.1007/s004390050350


Exon trapping was used to identify portions of human chromosome 21-encoded genes. More than 600 potential exons on the chromosome have been cloned and characterised to date. A BLAST search of databases revealed that three of these trapped “exons”, hmc18a08, hmc18f10 and hmc27g09, showed strong homology to different regions of the Drosophila mnb (Genbank X70794) and rat Dyrk (Genbank X79769) genes, indicating that these three exons may be portions of a human homologue of these genes (we termed this gene MNB for minibrain). With amplification by the polymerase chain reaction and hybridisation analysis we have mapped the human MNB gene on overlapping yeast artificial chromosomes 336G11 and 806A11 of chromosome 21q22.2 between markers D21S65 and ERG. The Drosophila mnb (minibrain) gene, which encodes a member of the protein kinase family, is involved in postembryonic neurogenesis. The Dyrk gene, which encodes a dual specificity protein kinase, is a rat homologue of the Drosophila mnb gene. The kinase activity is dependent on tyrosine residues in the catalytic domain, and it has been speculated that the protein is involved in control of the cell cycle. Altered expression of the human MNB gene may be involved in the pathogenesis of certain phenotypes of Down syndrome, including mental retardation.

Copyright information

© Springer-Verlag Berlin Heidelberg 1997

Authors and Affiliations

  • Haiming Chen
    • 1
  • Stylianos E. Antonarakis
    • 1
  1. 1.Laboratory of Human Molecular Genetics, Department of Genetics and Microbiology, University of Geneva Medical School, Geneva, SwitzerlandCH
  2. 2.Division of Medical Genetics, Cantonal Hospital, Geneva, SwitzerlandCH
  3. 3.Division de Genetique Medicale, Centre Medical Universitaire, 1 rue Michel Servet, CH-1211 Geneva, Switzerland Tel.: +41-22-7025707; Fax: +41-22-7025706; e-mail: sea@medsun.unige.chCH

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