The transmembrane domain of 5T4 is necessary for CXCR4 cell surface expression.

<p>(A), 5T4KO MEF were transduced with retroviral vectors encoding both eGFP and full length or truncated 5T4 or chimeric 5T4/CD44 constructs. Successful infection was assessed by GFP expression and the location of CXCR4, assessed in these cells. Cell surface expression of CXCR4 is only seen with constructs containing 5T4 TM (viii, xvi, xxiv); the extracellular and cytoplasmic domains of 5T4 are not required. (B), Consistent with this CXCL12 chemotaxis of the retrovirally transduced GFP+ 5T4 null MEF with 5T4 extracellular domain, (dark grey), 5T4 extracellular domain CD44 transmembrane and cytosolic domains, (grid) and mock infected, (white) showing no affect whereas full length 5T4, (light grey), 5T4 extracellular and transmembrane domains, (spots) and CD44 extracellular domain 5T4 transmembrane and cytosolic domains, (stripes) show comparable levels to wild-type (black columns).