MAST1 shares significant similarity with mouse Mast205 (MAST2). RT-PCR ELISA detected high expression in adult brain, spinal cord, and testis, in fetal brain, and in all specific adult brain regions examined. Expression was moderate in ovary, kidney, and fetal liver, low in pancreas, and very low or undetectable in all other tissues examined.
PCR analysis of rat tissues showed that, like Sast170, Sast124 was expressed exclusively in brain. Immunohistochemical analysis detected strong Sast124 staining in neurons of the subventricular zone and granule cells of the olfactory bulb, islands of Calleja, hippocampal dentate gyrus, and cerebellum. Sast124 localized in nuclei of neurons, in glia-like cell bodies in the corpus callosum, and in fiber bundles in the spinal trigeminal and solitary tracts.