H. Spits et al., Id2 and id3 inhibit development of CD34(+) stem cells into predendritic cell (Pre-DC)2 but not into Pre-DC1: Evidence for a lymphoid origin of Pre-DC2, J EXP MED, 192(12), 2000, pp. 1775-1783
We found previously that Id3, which inhibits transcriptional activities of
many basic helix-loop-helix transcription factors, blocked T and B cell dev
elopment but stimulated natural killer (NK) cell development. Here we repor
t that ectopic expression of Id3 and another Id protein, Id2, strongly inhi
bited the development of primitive CD34(+)CD38(-) progenitor cells into CD1
23(high) dendritic cell (DC)2 precursors. In contrast, development of CD34(
+)CD38(-) cells into CD4(+)CD14(+) DC1 precursors and mature DC1 was not af
fected by ectopic Id2 or Id3 expression. These observations support the not
ion of a common origin of DC2 precursors, T and B cells. As Id proteins did
not block development of NK cells, a model presents itself in which these
proteins drive common lymphoid precursors to develop into NK cells by inhib
iting their options to develop into T cells, B cells, and pre-DC2.