Use of simplified transcriptors for the analysis of gene expression profiles in laser-microdissected cell populations

Because colorectal epithelia are prone to malignant transformation, it is i mportant to understand their normal regulation and then to identify differe nces between the normal cells and the transformed cells. We investigated th e gene expression pattern along colonic crypts using a novel gene expressio n analysis strategy. We combined laser-mediated microdissection of distinct areas within colonic crypts and used modified RNA arbitrarily primed PCR t o generate probes for cDNA array hybridization. In the basal part of the cr ypt, proliferation-related and cell cycle-related genes such as the multifu nctional transcription factor e2f-1 or the mismatch-related gene p58/HHR23B were predominantly expressed. In the lumenal part of the crypt, up-regulat ions of the cysteine protease mch4 and the proto-oncogene c-jun were found. Our findings indicate that e2f1, p58/HHR23B, and mch4 may be involved in k ey mechanisms leading to malignant transformation in the colonic crypt. Our results also suggest that the technique elucidated here allows identificat ion of gene expression patterns in distinct areas of intestinal tissue samp les.