In quiescent large peritoneal macrophages (LPMs), the transcription
factors Maf and Mafb inhibit the expression of KLF4 and c-Myc, limiting
self-renewal. Cytokines, such as IL-4, induce the entry of LPMs into the cell
cycle. The progression of LPMs through the cell cycle is dependent on the
transcription factor Bhlhe40 and its ability to bind the promoter elements of
Maf and Mafb locus and represses their
transcription, thus leading to the increased expression of the pro-proliferative
transcription factors KLF4 and c-Myc.