5T4 is not required for CXCR7 surface expression.

<p>Immunofluorescence detection of 5T4 and CXCR7 in undifferentiated and differentiating WT and 5T4KO-ES cells (5T4 = green, CXCR7 = red). Cell surface expression of CXCR7 is high in undifferentiated ES cells (either WT or 5T4KO). In 3 day differentiating WT-ES cells, CXCR7 is relatively downregulated from the cell surface whereas in differentiating 5T4KO-ES surface CXCR7 is retained.