Analysis of gene expression in the programmed cell death of mouse limb buds *
Programmed cell death (PCD) is an important process for eliminating unnecessary tissues during embryonic development for proper morphogenesis at genetically determined stages. In this study, we analyzed transcriptional changes of 1176 genes in mouse limb programmed cell death (PCD) using DNA microarray technique. Many genes were up- or down-regulated during PCD. Homeobox genes Msx2, insulin-like growth factor binding protein 2 (IGFBP2) or apolipoprotein E (apoE) genes were up-regulated in interdigital PCD, revealed by DNA Expression Array using total RNA extracted from day 11.5 or 13.5 limb buds. Topological transcriptional patterns of selected genes were examined by in situ hybridization. PCD was revealed by Nile blue, HE staining or TUNEL method. In situ hybridization of apoE showed similar pattern as the Nile blue staining, and its expression was detected not in dying cells, but in macrophage-like cells. This observation suggested that apoE would be involved in engulfment of apoptotic cells. We found that its expression was also significantly reduced in BrdU-treated limbs, suggesting that apoE expression had been induced by unknown signals from dying cells. (Accepted on December 25, 2001) Kawasaki Igakkaishi 28 (1) : 33-42, 2002
