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Fig. 7. Xhmgb3 directly activates the transcription of Xenopus c-myc mRNA. (A) Northern blot analysis of total RNA from animal caps injected with water or Xhmgb3 RNA. A cDNA fragment of Xenopus c-myc was used as a labeled probe. Similar results were obtained in at least three independent experiments. The lower panel shows EtBr staining of ribosomal RNA. (B–F) Expression of Xenopus c-myc (B–D) or N-myc (E and F) or Xhmgb3 MO and β-gal RNA (C, E) or Xhmgb3 MO, Xhmgb3 RNA and β-gal RNA (D, F) into one dorsal blastomere at 4- or 8-cell stage on the animal side. Expression was examined at stages 13/14 (B–D) or stages 17/18 (E and F). The injected side is indicated by β-gal activity in blue (C–F). (G–K) ChIP analysis of Xhmgb3 for the c-myc promoter region. (G) Promoter region of Xenopus c-myc gene and designs of primers for PCR. (H–K) ChIP assay with primers for c-myc promoter region (H and I), for distal region with respect to promoter (J) or for c-myc protein-coding region (K). Immunocomplex was obtained from the extract of animal caps expressing 6x myc tag (H) or 6x myc-Xhmgb3 (I–K). ChIP assay was performed at least 4 times independently and showed same results. (L) Model of rax function in CNS development. Each molecule regulated by rax acts at different stages through distinct mechanisms, leading to normal development of the eye and brain. |
