Menin interacts directly with the homeobox-containing protein Pem

The tumour suppressor gene causing multiple endocrine neoplasia type 1 (MEN 1) encodes a 610 amino acid protein, menin. In order to identify menin-inte racting proteins we used a yeast two-hybrid assay to screen a 12.5-dpc mous e embryo library with partial menin encompassing amino acids 278 to 476. Th is identified a homeobox containing protein encoded by a placenta and embry onic expression gene, referred to as Pem. GST-pull-down and coimmunoprecipi tation experiments confirmed the interaction. Both proteins colocalised pre dominantly in the nucleus but were occasionally also found in the cytoplasm . Furthermore, in situ hybridisation studies revealed similarities in their expression patterns in mouse embryos and adult tissues. In adult mice both Men1 and Pem yielded strong signals in testis, Sertoli cells and particula rly in seminiferous tubules. Thus, our study has identified that menin inte racts with Pem, and the high expression of these proteins in the testis sug gests a role in spermatogenesis. (C) 2001 Academic Press.