wt c57bl/6 mice , csf2rb mice and the congenic strain b6.sjl-ptprc pepc / boyj ( b6.sjl ) were from the jackson laboratory .
mice were maintained in our specific pathogen - free animal facility according to institutional guidelines .
experiments used sex- and age - matched mice at 6 - 16 weeks of age .
1a was determined by microarrays for the long - term hematopoietic stem cell ( lt - hsc ) , flt3 multi - potent progenitor ( flt3 mpp ) , common myeloid progenitor ( cmp ) , granulocyte - macrophage progenitor ( gmp ) , common lymphoid progenitor ( clp ) , common dendritic cell progenitor ( cdp ) , bone marrow ( bm ) pre - cdc ( precdc ) , splenic pdc , splenic cd8 dc and splenic cd8 dc . in fig .
1b , lineage markers included ter119 , nk1.1 , b220 , mhcii , cd3 , and cd11b . for fig .
1c , cmp were lincd16/32-flt3ckit , cdp were lincd16/32flt3ckitcd115 , and pre - cdc were lincd16/32-flt3ckitcd11c . for fig .
1d - f , gating is as follows ; dcs , cd11cmhcii ; neutrophils ( pmn ) , ly6gcd11b ; monocytes ( mono ) , ly6ccd11bly6 g ; red pulp macrophages ( rpm ) , autofluorescent f4/80 ; nk cells nk1.1cd3 ; cd8 t cells ( cd8 t ) cd3cd8cd4 ; cd4 t cells ( cd4 t ) , cd3cd4cd8 ; and b cells , cd19b220siglech . in fig .
2 , pdcs were gated as cd11cmhcii cells ; resident dc as cd11cmhcii cells ; and migratory dcs as cd11cmhcii cells . in fig . 2c
, tissues were stained spleen , b220 ( blue ) ; f4/80 ( red ) ; gfp ( green ) ; lymph node b220 ( blue ) , cd169 ( red ) and gfp ( green ) ; small intestine cd4 ( blue ) , -catenin ( red ) and gfp ( green ) ; peyer 's patch cd4 ( blue ) , b220 ( red ) and gfp ( green ) . in fig .
2d , bm cells were cultured for 9 days with flt3 ligand , treated with media , interleukin 4 ( il-4 ) , interferon gamma ( ifn- ) , granulocyte - macrophage colony - stimulating factor ( gm - csf ) , and heat - killed listeria monocytogenes egd ( hklm ) for 24 hours .
wt c57bl/6 mice , csf2rb mice and the congenic strain b6.sjl-ptprc pepc / boyj ( b6.sjl ) were from the jackson laboratory .
mice were maintained in our specific pathogen - free animal facility according to institutional guidelines .
experiments used sex- and age - matched mice at 6 - 16 weeks of age .
1a was determined by microarrays for the long - term hematopoietic stem cell ( lt - hsc ) , flt3 multi - potent progenitor ( flt3 mpp ) , common myeloid progenitor ( cmp ) , granulocyte - macrophage progenitor ( gmp ) , common lymphoid progenitor ( clp ) , common dendritic cell progenitor ( cdp ) , bone marrow ( bm ) pre - cdc ( precdc ) , splenic pdc , splenic cd8 dc and splenic cd8 dc . in fig .
1b , lineage markers included ter119 , nk1.1 , b220 , mhcii , cd3 , and cd11b . for fig .
1c , cmp were lincd16/32-flt3ckit , cdp were lincd16/32flt3ckitcd115 , and pre - cdc were lincd16/32-flt3ckitcd11c . for fig .
1d - f , gating is as follows ; dcs , cd11cmhcii ; neutrophils ( pmn ) , ly6gcd11b ; monocytes ( mono ) , ly6ccd11bly6 g ; red pulp macrophages ( rpm ) , autofluorescent f4/80 ; nk cells nk1.1cd3 ; cd8 t cells ( cd8 t ) cd3cd8cd4 ; cd4 t cells ( cd4 t ) , cd3cd4cd8 ; and b cells , cd19b220siglech . in fig .
2 , pdcs were gated as cd11cmhcii cells ; resident dc as cd11cmhcii cells ; and migratory dcs as cd11cmhcii cells . in fig . 2c
, tissues were stained spleen , b220 ( blue ) ; f4/80 ( red ) ; gfp ( green ) ; lymph node b220 ( blue ) , cd169 ( red ) and gfp ( green ) ; small intestine cd4 ( blue ) , -catenin ( red ) and gfp ( green ) ; peyer 's patch cd4 ( blue ) , b220 ( red ) and gfp ( green ) . in fig .
2d , bm cells were cultured for 9 days with flt3 ligand , treated with media , interleukin 4 ( il-4 ) , interferon gamma ( ifn- ) , granulocyte - macrophage colony - stimulating factor ( gm - csf ) , and heat - killed listeria monocytogenes egd ( hklm ) for 24 hours .
 the transcription factors c - myc and n - myc encoded by myc and mycn , respectively , regulate cellular growth1 and are required for embryonic development2,3 . 
 a third paralog , mycl1 , is dispensable for normal embryonic development but its normal biologic function has remained unclear4 . to examine the in vivo function of mycl1 
 , we generated an inactivating mycl1gfp allele that also reports mycl1 expression . 
 we found that mycl1 was selectively expressed in dendritic cells ( dcs ) of the immune system and controlled by irf8 , and that during dc development , mycl1 expression was initiated in the common dc progenitor5 ( cdp ) concurrent with reduction in c - myc expression . 
 mature dcs lacked expression of c - myc and n - myc , but maintained l - myc expression even in the presence of inflammatory signals , such as gm - csf . 
 all dc subsets developed in mycl1-deficient mice , but several dc subsets , such as migratory cd103 + cdcs in the lung and liver , were significantly reduced at steady state . 
 importantly , loss of l - myc by dcs caused a significant decrease in the in vivo t - cell priming during infection by listeria monocytogenes and vesicular stomatitis virus . 
 the replacement of c - myc by l - myc in immature dcs may provide for myc transcriptional activity in the setting of inflammation that is required for optimal t - cell priming6 . 
Methods Summary
Mice