Differential pancreatic islet global gene expression in young heterozygous Men1 mice and wildtype littermates

Multiple Endocrine Neoplasia Tumor Syndrome type 1 (MEN 1) is an autosomal dominant tumor syndrome affecting individuals with a heterozygous germline mutaion of the MEN1 gene. MEN 1 carriers commonly develop parathyroid, anterior pituitary, duodenal and pancreatic endocrine tumors. The phenotype of existing mouse models for the MEN 1 syndrome, with a germline heterozygous (hz) Men1 gene inactivation, show close resemblance to the human MEN 1 syndrome. Menin, the protein encoded for by the MEN1/Men1 gene, lacks homology with known proteins, and evidence of its involvement in different cellular processes is steadily growing. Several interaction partners have been identified, involving different interaction sites on the menin protein. Accumulating evidence suggests a role for menin in transcriptional regulation, cell cycle control, apoptosis, chromatin modification and DNA damage response and repair. Loss of heterozygosity (LOH) of the MEN1 gene precedes tumor formation in the MEN 1 heterozygous pancreas. We set out to determine if there is a change in gene expression early on in the hz islet, as compared with islets in wildtype (wt) littermates, long before the LOH events occur. We performed a global mRNA expression microarray on islets from young, five-week-old, hz Men1 mice and their wt littermates, and we have subsequently corroborated a subset of the findings on the qPCR and protein level.

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Lejonklou MH, Barbu A, Stålberg P, Skogseid B