We have reported the predominant expression of ADAM22 mRNA in the human and mouse brain by Northern blot analysis [13,14]. To determine the distribution of ADAM22 transcript in the adult mouse CNS precisely, in situ hybridisation analysis was performed using 35S-labeled RNA probe. As shown in Fig. 3, ADAM22 mRNA was expressed throughout the adult mouse CNS. Strong signal was detected in the cerebellar granule cells and hippocampal formation. In the spinal cord, hybridisation signal was restricted to the grey matter. The distribution of ADAM22 transcripts in the CNS was quite similar with that of ADAM11, whose neuronal expression has been reported [19]. These results suggest that the ADAM22 mRNA expression is neuronal in the mouse CNS.