EXPRESSION OF THE APC TUMOR-SUPPRESSOR PROTEIN IN OLIGODENDROGLIA

Mutations of the adenomatous polyposis coli (APC) tumor suppressor gen e have been linked to familial polyposis, an inherited predisposition to colon cancer, and a high percentage of sporadic colon adenomas. Alt hough this gene is best known for its role in development of bowel neo plasms, in recent studies we have found that APC mRNA levels are great ly enriched in brain compared with peripheral tissues. To help define its role in the nervous system, in this study we have determined its c ellular localization immunohistochemically in adult rat brain sections and have detected intense APC immunoreactivity in oligodendrocytes. S ince prominent APC immunostaining is detected in cell bodies of mature oligodendrocytes, these antibodies may provide a useful addition to a vailable oligodendrocyte markers. Although the cellular function of AP C remains undefined, previous biochemical studies have demonstrated th at APC is associated with catenins, cytoplasmic proteins involved in r egulating cell-cell adhesion. We propose that, in addition to its crit ical role in ensuring normal maturation of colonic epithelial cells, t he APC tumor suppressor protein also regulates the adhesive properties of oligodendrocytes. (C) 1996 Wiley-Liss, Inc.