Kinetic analysis and pulse chase of A12L protein. A. To determine kinetic analysis of proteolytic processing of A12L, BSC-40 cells were infected with VV WR synchronously and harvested at different time courses as indicated above each lane. A 25 kDa protein corresponds to the A12L precursor (p17K), while smaller peptides with the molecular weights from 21 to 11 kDa are suspected to be the A12L cleavage products. B. Immunoprecipitation of pulse-chase labeled VV-infected cell extracts. Infected cells were labeled with [35 S]-methionine for an hour at 5 hpi and chased with 100× non-radioactive methionine/cysteine. Each pulse (P) and chase (C) of cells alone (Mock), rifampicin-treated (Rif+), and WR infected cell extracts (WR) were analyzed.