Identification Of A Novel Peptide That Binds Specifically To Mouse Es Cell By Phage Display

Embryonic stem cell (ES cell) has the pluripotent capability and self-renewal ability. Currently, it is not very clear about its mechanisms. Discovery of new receptor ligands are of great importance for the ES cell studies. By using phage display technology, 12-mer peptide ligands that bind specifically to mouse embryonic stem cells were isolated. The peptides obtained from bio-screen may lead a way to label, identify and characterize the MES cells. Also it could be conjugated with fluorescence dyes, medicaments or as a vector.In order to avoid non-specific peptide ligands, a negative-positive selection approach was applied. First, pre-incubate the library with differentiated mouse ES cells. Then incubate with the undifferentiated mouse ES cells. After four rounds of repeating selection, randomly select twenty clones. By DNA sequencing, nine different sequences were got. The result of ELISA suggested the Seq2 phage had high affinity and specificity to the mouse ES cells. Immunofluorescence analysis confirmed that Seq2 phage selectively bound to the MES cells but not to the differentiated mouse ES cells. Western analysis proved the Seq2 phage was bound to two MES membrane proteins which were about 18/20KD, suggested the selected peptide targeted to a unique receptor expressed on the mouse ES cells with specificity. All these results approved the selection was very effective. And the peptide selected was certainly specific to the mouse ES cells.