Figure Legends for Supplementary Information

Supplementary Figure 1:Deletion of the Ikk locus in IkkCol1KO mouse.

(a)Schematic representation of the IkkF/F and Ikkloci. Residual Ikk locus was amplified with primers Ex3-F and Ex3-R. Ikk was amplified with primers c and d.(b) Genomic DNA was prepared from each tissue of IkkCol1KO mouse and the Ikk fragment was amplified by PCR. (c) Quantification of the amount of Ikkin each tissue of IkkCol1KO mouse by qPCR(error bars; ± S.D.).Represented data are from one of three independent experiments.

Supplementary Figure 2:Loss of IKKβ in osteoblast lineage is dispensable for normal skeletal growth.

Length of crown-rump (a) and femur and tibia (b) of control and IkkF/F;Col1a1-Cre mice (n=8 in each group;error bars,± S.D.).

SupplementaryFigure 3: IKKβ in mesenchymal cells is dispensable for bone remodeling.

(a)Cancellous bone volume relative to the trabecularvolume (BV/TV) in distal femur of 4 and 8-week-old control and IkkF/F;Prx1-Cre mice (n=6 in each group). (b) Cortical bone volume relative to total volume (BV/TV) in distal femur of 8-week-old control and IkkF/F;Prx1-Cre mice (n=6 in each group). (c) Bone formation rate was calculated with calcein double labeling (n=6 in each group). (d, e) Osteoblast and osteoclast numbers in 8-week-old control and IkkF/F;Prx1-Cre mice. For all groups, n=6. Error bars, ± S.D.

Supplementary Figure 4:Deletion of the Ikk locus in IkkF/FMEF infected with Cre expression viral vector.

Specificity (a) and effectiveness (b) of deleting the Ikk locus were assessed by qPCR amplifyingIkk fragment and exon 3, respectively.Error bars,± S.D.

Supplementary Figure 5: Model illustrating the role of IKK in bone growth.

IKK in unstimulated perichondrial cells represses the expression of MCP-5 in a cell-autonomous manner. In the case Ikk is deleted in the perichondrium (in IkkPrx1KO), MCP-5 is up-regulated, secreted and binds to CCR2, which is expressed by cells in the hypertrophic zone. The binding of MCP-5 increases apoptosis and decreases chondrocyte hypertrophy. In parallel with theIKK-MCP-5 axis, MCP-5 is secreted from embryonic joint-forming cells in a TRII-dependent manner.

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