Figure 4

Downregulation of expression of macrophage PKC-α by recombinant mycobacteria expressing PknG. (A) The THP-1 cells infected with either wild type or recombinant mycobacteria were lysed, and equal amounts of total cell lysates (20 μg) were resolved by SDS-PAGE and immunoblotted with an antibody against PKCα. The lower parts of the blots were probed with an anti-tubulin antibody, to assure equal protein loading, (B) Densitometric analysis of blots shown in fig. 5A, (C) THP-1 cells infected with Rv were osmotically lysed and bacteria were recovered by centrifugation and total bacterial RNA was isolated. Total RNA was also isolated from bacterial suspension in RPMI-1640 medium which was used for infection of THP-1 cells. RNA samples were treated with DNAse I and cDNA were prepared using random hexamer primers and was used as template for Cyber Green real time PCR using pknG specific primers (values presented are normalized against 16S rRNA), Data are means ± standard deviations from five independent experiments each performed in 3 replicates. (** = p < 0.005). (D) experiment identical to 5A was performed with J774A.1 cells, (E) equal amounts of total cell lysates of J774A.1 cells infected with mycobacteria were immunoprecipitated with anti-PKC-α antibody and level of PKC-α was analyzed by immunoblotting. Same amounts of lysates were also immunoprecipitated with anti-tubulin antibody to serve as control, (F) Densitometric analysis of blots shown in fig. 5D, (G) Densitometric analysis of blots shown in fig.5E. The experiments were repeated at least 3 times.