Interference of EBNA-1 Binding to Ori-P by Cellular Proteins (ANTI-EBNA1)

Summary

We have previously shown by gel-shift assayori-p-DNA column chromatography and DNasel foatprinting, 2 species of cellular anti-EBNA1 proteins were produced by BJAB Dells upon activation by TPA (1, 2). These anti-E1 proteins could inhibit, compete and uncouple the sped fic binding of E iA-1 to the oir-p .Under denaturing conditions by SDS-PAGE, the molecular weight of the anti-EBNA1 proteins were 40,000 and 60,000, respectively. Here, we stowed that non-denaturing glycerol-gradient sedimentation was able to isolate the 40 kDa and 60 kDa anti-EBNAl that could bind to the 30 by repeat sequence of the EBV ori-p. Additionally, these anti-EBNA1 proteins were constitutively expressed by epithelial HeLa cells. Competitive gel-shift assay determined that the anti-EBNA1 proteins were not related to c-myc proteins. Our observations suggest that anti-EBNA1 may play a role in the preference for lytic infection when EBV infects epithelial cells, although the generality of anti-EBNAl expression in epithelial cells awaits confirmation.