A transcriptionally active form of TFIIIC is modified in poliovirus-infected HeLa cells.
A transcriptionally active form of TFIIIC is modified in poliovirus-infected HeLa cells.
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TFIIIC 的转录活性形式在脊髓灰质炎病毒感染的 HeLa 细胞中被修饰。
DOI：
10.1128/mcb.10.10.5106-5113.1990
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发表时间：
1990
影响因子：
5.3
通讯作者：
Dasgupta,A
中科院分区：
文献类型：
--
作者：
Clark,ME;Dasgupta,A
In HeLa cells, RNA polymerase III (pol III)-mediated transcription is severely inhibited by poliovirus infection. This inhibition is due primarily to the reduction in transcriptional activity of the pol III transcription factor TFIIIC in poliovirus-infected cells. However, the specific binding of TFIIIC to the VAI gene B-box sequence, as assayed by DNase I footprinting, is not altered by poliovirus infection. We have used gel retardation analysis to analyze TFIIIC-DNA complexes formed in nuclear extracts prepared from mock- and poliovirus-infected cells. In mock-infected cell extracts, two closely migrating TFIIIC-containing complexes, complexes I and II, were detected in the gel retardation assay. The slower migrating complex, complex I, was absent in poliovirus-infected cell extracts, and an increase occurred in the intensity of the faster-migrating complex (complex II). Also, in poliovirus-infected cell extracts, a new, rapidly migrating complex, complex III, was formed. Complex III may have been the result of limited proteolysis of complex I or II. These changes in TFIIIC-containing complexes in poliovirus-infected cell extracts correlated kinetically with the decrease in TFIIIC transcriptional activity. Complexes I, II, and III were chromatographically separated; only complex I was transcriptionally active and specifically restored pol III transcription when added to poliovirus-infected cell extracts. Acid phosphatase treatment partially converted complex I to complex II but did not affect the binding of complex II or III. Dephosphorylation and limited proteolysis of TFIIIC are discussed as possible mechanisms for the inhibition of pol III-mediated transcription by poliovirus.
