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Cell array-based intracellular localization screening reveals novel functional features of human chromosome 21 proteins

Yu-Hui Hu12, Hans-Jörg Warnatz1, Dominique Vanhecke1, Florian Wagner3, Andrea Fiebitz1, Sabine Thamm1, Pascal Kahlem14, Hans Lehrach1, Marie-Laure Yaspo1 and Michal Janitz1*

Author Affiliations

1 Department of Vertebrate Genomics, Max Planck Institute for Molecular Genetics, 14195 Berlin, Germany

2 FU Berlin, Department of Biology, Chemistry and Pharmacy, 14195 Berlin, Germany

3 RZPD German Resource Center for Genome Research, 14059 Berlin, Germany

4 Department of Hematology, Oncology, and Tumor Immunology, Humboldt University, Charite, Berlin, Germany

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BMC Genomics 2006, 7:155  doi:10.1186/1471-2164-7-155

Published: 16 June 2006



Trisomy of human chromosome 21 (Chr21) results in Down's syndrome, a complex developmental and neurodegenerative disease. Molecular analysis of Down's syndrome, however, poses a particular challenge, because the aneuploid region of Chr21 contains many genes of unknown function. Subcellular localization of human Chr21 proteins may contribute to further understanding of the functions and regulatory mechanisms of the genes that code for these proteins. Following this idea, we used a transfected-cell array technique to perform a rapid and cost-effective analysis of the intracellular distribution of Chr 21 proteins.


We chose 89 genes that were distributed over the majority of 21q, ranging from RBM11 (14.5 Mb) to MCM3AP (46.6 Mb), with part of them expressed aberrantly in the Down's syndrome mouse model. Open reading frames of these genes were cloned into a mammalian expression vector with an amino-terminal His6 tag. All of the constructs were arrayed on glass slides and reverse transfected into HEK293T cells for protein expression. Co-localization detection using a set of organelle markers was carried out for each Chr21 protein. Here, we report the subcellular localization properties of 52 proteins. For 34 of these proteins, their localization is described for the first time. Furthermore, the alteration in cell morphology and growth as a result of protein over-expression for claudin-8 and claudin-14 genes has been characterized.


The cell array-based protein expression and detection approach is a cost-effective platform for large-scale functional analyses, including protein subcellular localization and cell phenotype screening. The results from this study reveal novel functional features of human Chr21 proteins, which should contribute to further understanding of the molecular pathology of Down's syndrome.