Immediate Early Response 5 (IER5)

Williams et al. (1999) cloned a novel member of the slow-kinetics immediate-early response gene family, designated Ier5, from a mouse brain cDNA library.Mouse Ier5 encodes a deduced 308-amino acid protein with a predicted molecular mass of 31.9 kD. The N-terminal 49 amino acids show 57% sequence identity with those of the Ier2 protein. Ier5 contains 3 potential nuclear targeting signals, a possible PEST sequence, which suggests rapid protein degradation, and several potential phosphorylation sites. Northern blot analysis of total cellular RNA from serum-starved NIH 3T3 cells showed no detectable transcription in quiescent cells, but detected a single transcript within 30 minutes after exposure to serum. Transcription was also stimulated by the growth factors TPA, FGF, and PDGF, and did not appear to be dependent on protein kinase C activity.