Phospho-S103-HDGF expression in mitotic nuclei. (A) COS-7 cells were immunostained for HDGF or phospho-S103-HDGF and percentage positive cells determined. (B) Immunostaining of COS-7 cells (red) for total HDGF and middle panel for phospho-S103-HDGF. (C) Staining specificity was proven by pre-absorbing the phospho-S103-HDGF antibody with the S103 phosphopeptide (Pre-Ab) or omission of the phopho-S103 HDGF antibody (No primary). Cells were counterstained with DAPI to identify the nucleus and DNA.