Hoxa9 Hoxb3 Hoxb4

1. Department of Hematology School of Medical Sciences Tarbiat Modares University May.28.2008 Najmaldin saki

6. Results Hoxa9/b3/b4 null mice display a marked reduction in spleen size and cellularity

8. Hoxa9/b3/b4 and hoxa9 null CFU-S progenitors generate small spleen colonies

9. Lin- , Sca+ , c-Kit+ , CD 150+ (LSKCD150) Lin- , Sca+ , c-Kit+ , Cd34- , (LSKCD34-) Hoxa9/b3/b4 null mice exhibit an increase in the frequency of immunophenotypic HSCs

10. Loss of hoxb3 and hoxb4 does not exacerbate the repopulating defect observed in hoxa9¯’¯HSCs The key question emerging from this study is why the deficiency of hoxa9 alone results in such dramatic reduction in repopulating capacity and is not significantly compromised by the additional deletions (hoxb3/b4) ?