Structure of the Hmgb3 gene and protein. (A) Structure of Hmgb3 gene locus, mRNA, and protein. Top: schematic diagram of Hmgb3 gene locus (based on Vaccari et al).4 The entire locus is 4.4 kb flanked by PstI sites (P). There are 5 exons: white boxes represent untranslated regions, gray boxes represent translated regions. Bottom: Hmgb3 mRNA. The transcript is 1.5-kb long. Hmgb3 shares a highly conserved DNA binding domain with Hmgb1 and 2 (red bars). Green boxes represent putative nuclear localization signals based on Hmgb1 and 2 homology. The yellow bar represents the probe used for Northern blotting and in situ hybridization. (B) Nuclear localization of Hmgb3. Upper: constructs used to transfect 32D cells. Hmgb3 cDNA is fused in frame with the GFP gene. Lower: fluorescent microscopy of transfected 32D cells. DAPI staining was used to identify nuclei (blue). Green signals indicate Hmgb3-GFP protein. Some examples of overlapping signals are indicated by white arrows. Original magnification, × 400.
