P. Yalamanchili et al., POLIOVIRUS-ENCODED PROTEASE 2A(PRO) CLEAVES THE TATA-BINDING PROTEIN DOES NOT INHIBIT HOST-CELL RNA-POLYMERASE-II TRANSCRIPTION IN-VITRO, Journal of virology, 71(9), 1997, pp. 6881-6886
Transient expression of the poliovirus-encoded protease 2A(Pro) in euk
aryotic cells results in inhibition of both cellular transcription and
translation. The inhibition of transcription observed in cells expres
sing 2A(Pro) could be due to a primary effect dr secondary effect caus
ed by inhibition of: translation. Because transcriptional activity of
the TATA-binding protein (TBP) is drastically reduced in poliovirus-in
fected cells, we determined if 2A(Pro) is able to Cleave TBP in vitro.
We demonstrate here that 2A(Pro) directly cleaves the single tyrosine
-glycine bond at position 34 of TBP, This cleavage is also seen in pol
iovirus-infected HeLa cells. Surprisingly, despite TBP cleavage 2A(Pro
) was unable to inhibit RNA polymerase II transcription in vitro. Unde
r similar conditions, however, 2A(Pro) inhibited translation of a capp
ed cellular mRNA in vitro. Thus, cleavage of TBP ai position 34 does n
ot alter its transcriptional activity in vitro. These results suggest
that inhibition of host cell RNA polymerase II transcription seen in c
ells transiently transfected with 2A(Pro) is due to host cell translat
ional shutoff.