Journal Article

Mice deficient for the chromosome 21 ortholog <i>Itsn1</i> exhibit vesicle-trafficking abnormalities

Yong Yu, Po-Yin Chu, David N. Bowser, Damien J. Keating, Daphne Dubach, Ian Harper, Josephine Tkalcevic, David I. Finkelstein and Melanie A. Pritchard

in Human Molecular Genetics

Volume 17, issue 21, pages 3281-3290
Published in print November 2008 | ISSN: 0964-6906
Published online August 2008 | e-ISSN: 1460-2083 | DOI: http://dx.doi.org/10.1093/hmg/ddn224
Mice deficient for the chromosome 21 ortholog Itsn1 exhibit vesicle-trafficking abnormalities

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Enlarged early endosomes in the neurons of young Down syndrome (DS) and pre-Alzheimer’s disease (AD) brains suggest that a disturbance in endocytosis is one of the earliest hallmarks of AD pathogenesis in both conditions. We identified a chromosome 21 gene, Intersectin-1 (ITSN1) that is up-regulated in DS brains and has a putative function in endocytosis and vesicle trafficking. To elucidate the function of ITSN1 and assess its contribution to endocytic defects associated with DS and AD, we generated Itsn1 null mice. In knockout mice we found alterations in a number of parameters associated with endocyic and vesicle trafficking events. We found a reduced number of exocytosis events in chromaffin cells and a slowing of endocytosis in neurons. Endosome size was increased in neurons and NGF levels were reduced in the septal region of the brain. Our data is the first indication that Itsn1 has a role in endocytosis in an in vivo mammalian model, and that a disruption in Itsn1 expression causes a disturbance in vesicle trafficking and endocytic function in the brain. These results imply a role for ITSN1 in the early endocytic anomalies reported in DS brains which may have ramifications for the onset of AD.

Journal Article.  6961 words.  Illustrated.

Subjects: Genetics and Genomics

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