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Expression of a human insulin transgene in cholinergic neurons of the mouse medial habenula
Author(s) -
Douhet Philippe,
Destrade Claude,
Bucchini Danielle,
Calas André
Publication year - 1995
Publication title -
biology of the cell
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.543
H-Index - 85
eISSN - 1768-322X
pISSN - 0248-4900
DOI - 10.1016/0248-4900(96)85274-9
Subject(s) - habenula , biology , interpeduncular nucleus , proinsulin , transgene , human brain , insulin , amylin , microbiology and biotechnology , neuroscience , gene , genetics , central nervous system , endocrinology , islet , midbrain
Summary— We explored the possibility that an insulin gene deleted in its 5'‐flanking region is expressed in adult mouse brain. We used three independent lines of mice carrying a human insulin transgene which included the insulin gene transcription unit flanked by 168 base pairs upstream and 5.5 kb downstream. Using a reverse transcription‐polymerase chain reaction assay, human insulin mRNAs were detected in whole brain extracts. In all three lines, human insulin mRNAs were localized by in situ hybridization in a single cerebral site, the medial habenula. With a monoclonal antibody specific for human C‐peptide and human proinsulin, labelling was restricted to a subset of habenular cholinergic neurons, with rare immunostained fibers. No labelling was observed in the projection fibers of the retroflexus fasciculus or in their axon terminals in the interpeduncular nucleus. Electron microscope studies suggested that the processing of the human peptide involved the endoplasmic reticulum and Golgi apparatus, but there were no secretory granules in the transgene expressing cells. These findings demonstrate that the human insulin transgene tested here includes a habenula specific promoter which could be useful for physiological and molecular studies on the habenula.