Developmental expression and localization of IA-2 mRNA in mouse neuroendocrine tissues

Islet antigen (IA)-2 is a novel autoantigen of insulin-dependent diabetes m ellitus (IDDM), and belongs to a new class within the receptor-type protein tyrosine phosphatase (PTP) family characterized by lack of PTP enzymatic a ctivity with conventional substrates. Its expression is restricted primaril y to the pancreas, pituitary, and brain with the highest level in the brain . IA-2 mRNA expressions in the brain, pituitary and pancreas of 1-, 4-, and 8-week-old mice were examined. In situ hybridization of the brain revealed that IA-2 mRNA was expressed in the cerebral cortex, hippocampus, thalamus , choroid plexus, hypothalamus, Purkinje cells, and granular layer of the c erebellum. In the pituitary, IA-2 mRNA was located in the anterior and post erior pituitary by in situ hybridization. The pattern of IA-2 mRNA expressi on in normal male mouse brain at 1, 4, and 8 weeks of age by the Northern b lot analysis was similar to that in the pituitary by RT-PCR analysis. The e xpression level was higher at 4 weeks and lower at I week of age. In the pa ncreas, IA-2 mRNA expressions detected by RT-PCR were highest at 8 weeks of age. These results indicated that the amount of mRNA expression increased in accordance to development in brain, pituitary, and pancreas. (C) 2001 Ac ademic Press.