Influence of 3’-UTR AREs on luciferase reporter expression in MK cells that express or lack integrin α3β1.

<p>(A) Schematic of CMV promoter-driven luciferase reporter genes containing pentamers that encode either consensus AU-rich ARE sequences or control GC-rich sequences within the 3’-UTR of the mRNA. Reporter plasmids were transfected into α3-expressing MK+/+ cells or α3-null MK−/− cells, and experimental luciferase signals were normalized to that for a co-transfected <i>Renilla</i> luciferase control plasmid (pRLTK). Graph shows luciferase activity from the AU-rich reporter relative to that from the GC-rich reporter. (B) Schematic of MMP-9 promoter-driven luciferase reporter genes containing either the MMP-9 3’-UTR or the SV40 poly(A) signal downstream of luciferase coding sequences. MK+/+ cells or MK−/− cells were co-transfected with reporter and control plasmids as in (A). Graph shows luciferase activity from the MMP-9 3’-UTR reporter relative to that from the SV40 poly(A) reporter. For (A) and (B), MK cells were seeded onto LN-332-rich ECM and transfected for 24 hours, then luciferase expression was assayed as described in the Materials and Methods. Data are the mean of three independent experiments +/- s.e.m.