RNAase protection assays demonstrated that the MMP9 activity , unique to infected cells , is due to increased MMP9 mRNA levels .
rnaase protection assays demonstrated that the mmp9 activity , unique to infected cells , is due to increased mmp9 mrna levels .
B-protein_molecule O O O O O B-protein_molecule O O O O B-cell_type I-cell_type O O O O O B-protein_molecule O O O