Knockdown of endogenous EXTL2 and EXTL3. 293T cells were transfected with shEXTL2, shEXTL3 or ctrlEXTL pENTR/U6 constructs. After 72 h, total RNA was extracted and reverse transcribed to generate cDNA. EXTL2 or EXTL3 expression was determined by real-time PCR, and the fold change in expression was expressed as a percentage of the untransfected control and compared with a mock-transfected control (lipofectamine 2000 reagent only). Results are the mean±standard deviation of n=3 replicates. *Significant difference from mock transfection, P<0.001 (ANOVA, Tukey's HSD).