Cxcl12 (chemokine (C-X-C motif) ligand 12) regulates many hematopoietic and non-hematopoietic cell types. CXCL12 is constitutively expressed at high levels in many bone marrow stromal cell types, where it contributes to both hematopoietic stem cell (HSC) and lymphoid progenitor maintenance. Exon 2 of the mouse gene is flanked by loxP sites in this conditional targeted mutation. Cre recombinase-mediated excision of the floxed region enables tissue/cell-specific knockouts of the gene, useful in studies of hematopoietic stem cell maintenance or other CXCL12-dependent processes.
Osx-Cre (Sp7-Cre, see Stock No. 006361)-mediated deletion of Cxcl12 from Sp7 transcription factor 7 (osterix)-expressing stromal cells, which include CXCL12-abundant reticular cells and osteoblasts, results in constitutive hematopoietic progenitor cell (HPC) mobilization and a loss of B-lymphoid progenitors, but HSC function is normal.
Tie2-Cre (Tek-Cre, see Stock No. 008863)- mediated deletion of Cxcl12 from endothelial cells results in a modest loss of long term repopulating activity.
Strikingly, deletion of Cxcl12 from mesenchymal progenitors using Prx1-Cre (Prrx1-Cre, see Stock No. 005584) is associated with a marked loss of HSCs, long term repopulating activity, HSC quiescence and common lymphoid progenitors.
Deletion of Cxcl12 from mineralizing osteoblasts via osteocalcin-Cre (BGLAP-Cre, see Stock No. 019509) crosses has no effect on HSCs or lymphoid progenitors.
