Genes induced in programmed cell death of neuronal PC12 cells and developing sympathetic neurons in vivo.

To identify primary response genes induced during early stages of neuronal programmed cell death (PCD), we screened by differential hybridization a subtracted cDNA library prepared from neuronal PC12 cells deprived of NGF for 6 hr in the presence of cycloheximide. Eight induced cDNA sequences were identified and designated message up-regulated during death (mud)-1-8. To determine which cloned sequences might be involved in neuronal PCD in vivo, expression of mud genes was analyzed in developing rat superior cervical ganglia (SCG) undergoing programmed cell death, using a combination of reverse Southern, reverse transcription polymerase chain reaction (RT-PCR), and in situ hybridization. Five sequences (mud-1, -3, -5/8, -6, and -7) are induced in SCG undergoing cell death in vivo, and induction of at least three of these (mud-3, -6, and -7) occurs in neurons. Partial sequence analysis reveals that mud-1 corresponds to annexin VI; mud-3 corresponds to rat PC3, mouse TIS21; mud-4 appears to be the rat homolog of human TAFII70; mud-5 and -8 are >85% identical members of the rodent gene family of B2-transcribed repeats; and mud-6 appears to be the rat homolog of human Ring 3 and Drosophila female sterile homeotic (fsh). Mud-2 and mud-7 encode novel sequences. These new candidate genes provide markers for early stages of neuronal PCD, are potentially involved in the cell death process, and serve to expand our view of cell death control in the developing nervous system.