ADAMTS-12 and Trophoblast Invasion Figure 1. Characterization of the ADAMTS subtypes present in human placenta and trophoblastic cells. (A) Representative autoradiograms of Southern blots containing PCR products synthesized from total RNA from first trimester placenta, JEG-3 cells or EVTs using primers specific for the indicated ADAMTS or GAPDH. The presented results are densitometry readings showing mean 6 SEM (n$4; * = P#0.05). (B) A representative Western blot containing total protein prepared from first trimester placenta, EVTs or JEG-3 cells, was probed with a polyclonal antibody against ADAMTS-12. The blots were re-probed with monoclonal against human b-actin. The molecular weight markers (kDa) are shown to the left. doi:10.1371/journal.pone.0018473.g001 filters were found to be significantly and consistently fewer in cultures of EVTs transfected with A12i compared to controls (Figure 3C). Exogenous ADAMTS-12 induces invasion in JEG-3 cells To determine whether exogenous ADAMTS-12 expression could confer an invasive phenotype on trophoblastic cells, JEG-3 cells were stably transfected with the expression vector A12FL; the catalytic activity of the expressed ADAMTS-12 protein species has been verified in previous studies derived from the same expression construct used in this study [21,27]. Similar to our preceding observations, a major ADAMTS-12 protein species (83 kDa) was readily detectable in these JEG-3 cells but not in those transfected with the control LacZ expression vector (Figure 4A). In addition to PLoS ONE | www.plosone.org 5 April 2011 | Volume 6 | Issue 4 | e18473