Fig 2: Id3 acted as an effector of canonical BMP signal during aging. (A) Transcription level of Id3 in ctrl and BMP4 treated C17.2 mouse stem cells analyzed by qPCR. n = 3. *** p < 0.001. (B) Representative images of Id3 and BrdU immunostaining in ctrl and BMP4 treated C17.2 mouse stem cells. Scale bar, 100 µm. (C) Calculation of Id3 expression in ctrl and BMP4 treated C17.2 mouse stem cells. *** p < 0.001. (D) Calculation of BrdU positive cells in ctrl and BMP4 treated C17.2 mouse stem cells. * p < 0.05. (E) Representative images of Id3 and BMP4 colocalization in the SVZ and SGZ of 14 MO female mice. Scale bar, 50 µm. (F) Representative images of Id3 expression in the SVZ and SGZ of female mice at 2, 8, 12 and 18 MO. Scale bar, 50 µm. (G) Western blotting analyses of proteins extracted from the SVZ and SGZ of three mice at 2, 8, 14 and 28 MO. ß-actin is used as a loading control. (H,I) Relative quantification of Western blotting analysis of Id3 levels in the SVZ (H) and SGZ (I) of female mice at 2, 8, 14 and 28 MO. Data is represented as the mean protein intensity normalized to ß-actin ± S.E.M. from 3 independent mice. * p < 0.05, ** p < 0.01 and *** p < 0.001. (J) Representative images of Id3 expression in the SVZ and SGZ of female mice at 10 MO after saline, BMP4 and noggin infusion. Scale bar, 50 µm. (K) Western blotting analyses of proteins extracted from the SVZ and SGZ of three mice at 10 MO after saline, BMP4 and noggin infusion. ß-actin is used as a loading control. (L,M) Relative quantification of Western blotting analysis of Id3 levels in the SVZ (L) and SGZ (M) after the various treatments. Data is represented as the mean protein intensity normalized to ß-actin ± S.E.M. from 3 independent mice in each group. ** p < 0.01. (N) Representative images of BrdU and DCX positive cells in the SVZ and SGZ from 9 MO female mice ten days after mice were grafted twice with lentivirus expressing negative control (NC) and wild type Id3 (Id3-WT). Scale bar, 50 µm. (O) Quantification of BrdU and DCX positive cells in the SVZ from 9 MO female mice ten days after mice were grafted with lentivirus expressing negative control (NC) and wild type Id3 (Id3-WT). * p < 0.05 and ** p < 0.01. (P) Quantification of BrdU and DCX positive cells in the SGZ from 9 MO female mice ten days after mice were grafted with lentivirus expressing negative control (NC) and wild type Id3 (Id3-WT). * p < 0.05 and ** p < 0.01.