Table 1.

Transcription factors regulating microglia development and homeostasis.

Transcription factor	Microglia development	Microglia homeostasis
c-myb	→ Independent of c-myb (Schulz et al., 2012; Kierdorf et al., 2013)	→ After induced ablation of c-myb, no change in microglia cell number (Schulz et al., 2012)
Runx-1	→ Expressed on microglia progenitors in the yolk sac (Ginhoux et al., 2010)	→ Regulating proliferation and tissue homeostasis of postnatal microglia (Zusso et al., 2012)
		→ Transition of amoeboid to ramified morphology (Zusso et al., 2012)
Pu.1	→ Absence of microglia progenitors in the yolk sac; no development of microglia (Scott et al., 1994; McKercher et al., 1996; Beers et al., 2006; Schulz et al., 2012; Kierdorf et al., 2013)	→ No direct evidence yet for a functional role during microglia cell homeostasis
Irf8	→ Reduced number of microglia and microglial progenitors in the yolk sac (Kierdorf et al., 2013)	→ Dysregulation of microglial cell morphology and function (Horiuchi et al., 2012; Minten et al., 2012)
		→ Defects in microglial activation (Masuda et al., 2012)
Hoxb8	→ No direct evidence yet for a functional role during microglia development	→ Mutant Hoxb8 microglia induce pathological grooming in mice (Chen et al., 2010)