Journal Article

A Human Homologue of <i>Drosophila Minibrain (Mnb</i>) Is Expressed in the Neuronal Regions Affected in Down Syndrome and Maps to the Critical Region

Jordi Guimerâ, Caty Casas, Carles Pucharcôs, Asun Solans, Anna Domènech, Anna M. Planas, Jennifer Ashley, Michael Lovett, Xavier Estivill and Melanie A. Pritchard

in Human Molecular Genetics

Volume 5, issue 9, pages 1305-1310
Published in print September 1996 | ISSN: 0964-6906
e-ISSN: 1460-2083 | DOI:
A Human Homologue of Drosophila Minibrain (Mnb) Is Expressed in the Neuronal Regions Affected in Down Syndrome and Maps to the Critical Region

Show Summary Details


The minibrain (mnb) gene of Drosophila melanogaster encodes a serine-threonine protein kinase with an essential role in postembryonic neurogenesis. A corresponding human gene with similar function to mnb could provide important insights into both normal brain development and the abnormal brain development and mental retardation observed in many congenital disorders. Trisomy 21 or Down syndrome (DS) is the most frequent human birth defect. It is associated with mental retardation and a broad spectrum of physical abnormalities. A region on human chromosome 21 has been designated the Down syndrome critical region (DSCR) and when present in three copies, this is responsible for many of the characteristic features of DS, including mental retardation. We have isolated a human homologue of mnb from the DSCR. MNB encodes a 6.1 kb transcript which is expressed in foetal brain, lung, kidney and liver. Using a human probe, two major transcripts (6.1 and 3.1 kb) were identified in mouse and expression was detected in situin several regions of the mouse brain, including the olfactory bulb, the cerebellum, the cerebral cortex, the pyramidal cell layer of the hippocampus and several hypothalamic nuclei. This expression pattern corresponds to the regions of the brain that are abnormal in individuals with DS and suggests that overexpression of MNB could have detrimental consequences in DS patients.

Journal Article.  3569 words.  Illustrated.

Subjects: Genetics and Genomics

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