CDF/LIF selectively increases c-fos and jun-B transcripts in sympathetic neurons.

We recently demonstrated that the neuronal cholinergic differentiation factor (CDF) which switches the neurotransmitter phenotype of cultured sympathetic neurons from noradrenergic to cholinergic is identical to leukemia inhibitory factor (LIF). To elucidate some of the initial events leading to the phenotypic switch, the effects of CDF/LIF on the mRNA levels of several immediate early genes were examined in cultured neonatal rat sympathetic neurons. c-fos and jun-B were induced within 30 min of addition of CDF/LIF. In contrast, no effect on the expression of c-myc, fra-1, v-jun or actin mRNA was detected at this time. Thus, CDF/LIF may induce the expression of particular immediate early genes prior to its positive and negative effects on neurotransmitter and neuropeptide gene expression.