Pin1 modulates the structure and function of human RNA polymerase II

By using micro disc electrophoresis and micro-diffusion techniques, the interaction of pure DNA-dependent RNA polymerase (EC 2.7.7.6) from Escherichia coli with the template, the substrates and the inhibitors heparin and rifampicin was investigated. The following findings were obtained: (1) heparin converts the 24S and 18S particles of the polymerase into the 13S form; (2) heparin inhibits RNA synthesis by dissociating the enzyme–template complex; (3) rifampicin does not affect the attachment of heparin to the enzyme; (4) the substrates ATP and UTP are bound by enzyme loaded with rifampicin; (5) rifampicin is bound by an enzyme–template complex to the same extent as by an RNA-synthesizing enzyme–template complex. From this it is concluded that the mechanism of the inhibition of RNA synthesis by rifampicin is radically different from that by heparin. As a working hypothesis to explain the inhibitory mechanism of rifampicin, it is assumed that it becomes very firmly attached to a position close to the synthesizing site and only blocks this when no synthesis is in progress.

Download Full-text

Dynamics: the missing link between structure and function of the viral RNA-dependent RNA polymerase?

Current Opinion in Structural Biology ◽

10.1016/j.sbi.2009.10.012 ◽

2009 ◽

Vol 19 (6) ◽

pp. 768-774 ◽

Cited By ~ 40

Author(s):

Craig E Cameron ◽

Ibrahim M Moustafa ◽

Jamie J Arnold

Keyword(s):

Rna Polymerase ◽

Structure And Function ◽

Viral Rna ◽

Rna Dependent Rna Polymerase ◽

Missing Link ◽

And Function

Download Full-text

Azotobacter vinelandii RNA polymerase. XIV. Role of sulfhydryl groups in the structure and function of the Azotobacter vinelandii RNA polymerase

Biochemistry ◽

10.1021/bi00691a029 ◽

1975 ◽

Vol 14 (20) ◽

pp. 4522-4527 ◽

Cited By ~ 3

Author(s):

Joseph S. Krakow

Keyword(s):

Rna Polymerase ◽

Azotobacter Vinelandii ◽

Structure And Function ◽

Sulfhydryl Groups ◽

And Function

Download Full-text

Human RNA polymerase II subunit hsRPB7 functions in yeast and influences stress survival and cell morphology.

Molecular Biology of the Cell ◽

10.1091/mbc.6.7.759 ◽

1995 ◽

Vol 6 (7) ◽

pp. 759-775 ◽

Cited By ~ 52

Author(s):

V Khazak ◽

P P Sadhale ◽

N A Woychik ◽

R Brent ◽

E A Golemis

Keyword(s):

Rna Polymerase ◽

Rna Polymerase Ii ◽

Specific Pattern ◽

Yeast Cells ◽

Human Genes ◽

Complete Set ◽

High And Low Temperatures ◽

And Function ◽

Two Hybrid ◽

Potential Regulatory Role

Using a screen to identify human genes that promote pseudohyphal conversion in Saccharomyces cerevisiae, we obtained a cDNA encoding hsRPB7, a human homologue of the seventh largest subunit of yeast RNA polymerase II (RPB7). Overexpression of yeast RPB7 in a comparable strain background caused more pronounced cell elongation than overexpression of hsRPB7. hsRPB7 sequence and function are strongly conserved with its yeast counterpart because its expression can rescue deletion of the essential RPB7 gene at moderate temperatures. Further, immuno-precipitation of RNA polymerase II from yeast cells containing hsRPB7 revealed that the hsRPB7 assembles the complete set of 11 other yeast subunits. However, at temperature extremes and during maintenance at stationary phase, hsRPB7-containing yeast cells lose viability rapidly, stress-sensitive phenotypes reminiscent of those associated with deletion of the RPB4 subunit with which RPB7 normally complexes. Two-hybrid analysis revealed that although hsRPB7 and RPB4 interact, the association is of lower affinity than the RPB4-RPB7 interaction, providing a probable mechanism for the failure of hsRPB7 to fully function in yeast cells at high and low temperatures. Finally, surprisingly, hsRPB7 RNA in human cells is expressed in a tissue-specific pattern that differs from that of the RNA polymerase II largest subunit, implying a potential regulatory role for hsRPB7. Taken together, these results suggest that some RPB7 functions may be analogous to those possessed by the stress-specific prokaryotic sigma factor rpoS.

Download Full-text