Arginine/glycine-dependent creatine biosynthesis is required for the reduction of histone methylation and the methionine-deprived specific gene response.

(A) Relative expression levels of TEX14, DAPK3, Egr1 and ING2 by qPCR in MCF7 after depletion of either methionine (-M), or both methionine and serine (-M-S), or both methionine and glycine (-M-G), or methionine, serine and glycine (-MSG) for 24 hours (n = 3; *, p < 0.01). (B, C) Western blot analysis of histone H3 (control) and indicated histone methylations in MCF7 (B) or PC3 (C) after deprivation of methionine (-M), arginine (-R) or both methionine and arginine (-M-R) for 24 hours. (D) The levels of SAM and MTA in MCF7 cells after indicated time deprivation of methionine (-M), or both methionine and arginine (-MR) (n = 3; #, p < 0.01; ##, p< 0.01). (E) Relative expression levels of AGAT, GAMT, Tex14, DPAK3 and ING2 by qPCR in shRNA scramble (scr) and silenced AGAT (shAGAT) or GAMT (shGAMT) MCF7 cells after 24 hours of methionine deprivation (n = 3; **, p< 0.05).