2D-DIGE analysis of primitive hematopoietic cells. (A) Workflow for proteomic analysis of Lin^–Sca⁺Kit⁺ and Lin^–Sca⁺Kit^– using Cy dye reagents. The protocol outlined above allows comparison of protein expression profiles, relative protein quantification, and identification of proteins of interest. (B) Representative 2D gel images of Lin^–Sca⁺Kit⁺ and Lin^–Sca⁺Kit^– cells labeled with saturation dyes. The 2 images shown are from a saturation-labeled Cy dye protein gel where the excitation and emission wavelengths were set for Cy3 (left image) or Cy5 (right image). The grayscale 3-dimensional representations show representative gels from Lin^–Sca⁺Kit^– and Lin^–Sca⁺Kit⁺ labeled with Cy3 and Cy5, respectively.