Biogenesis of RNA Polymerases II and III Requires the Conserved GPN Small GTPases in Saccharomyces cerevisiae

@article{Minaker2013BiogenesisOR,
  title={Biogenesis of RNA Polymerases II and III Requires the Conserved GPN Small GTPases in Saccharomyces cerevisiae},
  author={Sean W. Minaker and Megan C. Filiatrault and Shay Ben-Aroya and Philip Hieter and Peter C. Stirling},
  journal={Genetics},
  year={2013},
  volume={193},
  pages={853 - 864}
}
The GPN proteins are a poorly characterized and deeply evolutionarily conserved family of three paralogous small GTPases, Gpn1, 2, and 3. The founding member, GPN1/NPA3/XAB1, is proposed to function in nuclear import of RNA polymerase II along with a recently described protein called Iwr1. Here we show that the previously uncharacterized protein Gpn2 binds both Gpn3 and Npa3/Gpn1 and that temperature-sensitive alleles of Saccharomyces cerevisiae GPN2 and GPN3 exhibit genetic interactions with… 

Figures from this paper

Npa3 interacts with Gpn3 and assembly factor Rba50 for RNA polymerase II biogenesis
TLDR
It is shown here that rapid degradation of each GPN protein in yeast leads to cytoplasmic accumulation of Rpb1 and defects in the assembly of RNA polymerase II, suggesting conserved functions of GPN paralogs for RNA polymerases II biogenesis as in humans.
A nuclear proteome localization screen reveals the exquisite specificity of Gpn2 in RNA polymerase biogenesis
TLDR
Overall, this screen shows the exquisite specificity of GPN2 for RNA polymerase transport, and reveals a previously unappreciated role for CTD modification in RNAPII nuclear localization.
Npa3-Gpn3 cooperate to assemble RNA polymerase II and prevent clump of its subunits in the cytoplasm.
Structure of GPN-Loop GTPase Npa3 and Implications for RNA Polymerase II Assembly
TLDR
It is shown that Npa3 has chaperone activity and interacts with hydrophobic peptide regions of Pol II subunits that form interfaces in the assembled Pol II complex, suggesting that GPN-loop GTPases are assembly chaperones for Pol II and other protein complexes.
Rbs1, a New Protein Implicated in RNA Polymerase III Biogenesis in Yeast Saccharomyces cerevisiae
TLDR
It is demonstrated that a missense cold-sensitive mutation, rpc128-1007, in the sequence encoding the C-terminal part of the second largest Pol III subunit, C128, affects the assembly and stability of the enzyme and postulate that Rbs1 binds to the Pol III complex or subcomplex and facilitates its translocation to the nucleus.
The expression of Rpb10, a small subunit common to RNA polymerases, is modulated by the R3H domain-containing Rbs1 protein and the Upf1 helicase
TLDR
It is proposed that Rbs1 functions by opposing mRNA degradation, at least in part mediated by NMD pathway, and is a conserved regulatory mechanism for Pol III biogenesis.
A Role for MINIYO and QUATRE-QUART2 in the Assembly of RNA Polymerases II, IV, and V in Arabidopsis
TLDR
These findings reveal IYO and QQT2 as cofactors for the assembly of Pol II, Pol IV, and Pol V and provide mechanistic insights into how RNA polymerases are assembled in plants.
Gpn2 and Rba50 Directly Participate in the Assembly of the Rpb3 Subcomplex in the Biogenesis of RNA Polymerase II
TLDR
It is concluded that Gpn2 and Rba50 directly participate in the assembly of the Rpb3 subcomplex and subsequently the biogenesis of RNAPII.
...
1
2
3
4
...

References

SHOWING 1-10 OF 45 REFERENCES
Human GTPases Associate with RNA Polymerase II To Mediate Its Nuclear Import
TLDR
GPN1/GPN3 define a new family of small GTPases that are specialized for the transport of RNA polymerase II into the nucleus and a role for these proteins in nuclear import of RNAPII is demonstrated.
GTP-dependent Binding and Nuclear Transport of RNA Polymerase II by Npa3 Protein*
TLDR
Npa3 defines an unconventional pathway for nuclear import of RNAPII, which involves GTP-dependent binding of Npa3 to the polymerase, which is significantly increased by the addition of GTP or its slowly hydrolyzable analogue guanosine 5′-3-O-(thio)triphosphate (GTPγS).
The Protein Interaction Network of the Human Transcription Machinery Reveals a Role for the Conserved GTPase RPAP4/GPN1 and Microtubule Assembly in Nuclear Import and Biogenesis of RNA Polymerase II*
TLDR
RPAP4/GPN1 is a member of a newly discovered GTPase family that contains a unique and highly conserved GPN loop motif that is essential, in conjunction with its GTP-binding motifs, for nuclear localization of POLR2A/RPB1 in a process that also requires microtubule assembly.
Iwr1 Protein Is Important for Preinitiation Complex Formation by All Three Nuclear RNA Polymerases in Saccharomyces cerevisiae
TLDR
Iwr1 plays an important role in preinitiation complex formation by all three nuclear RNA polymerases, including Pol III transcription, in S. cerevisiae.
Regulating the Shuttling of Eukaryotic RNA Polymerase II
TLDR
It is reported that the evolutionarily conserved GTPases GPN1 and GPN3 stably associate with and regulate the nuclear import of the human RNAPII, and this GTPase family has been highly conserved during evolution and is also present in yeast.
RNA polymerase II subunit RPB4 is essential for high- and low-temperature yeast cell growth.
TLDR
The RPB4 subunit, although not essential for mRNA synthesis or enzyme assembly, was essential for normal levels of RNA polymerase II activity and indispensable for cell viability over a wide temperature range.
Iwr1 directs RNA polymerase II nuclear import.
Parcs/Gpn3 is required for the nuclear accumulation of RNA polymerase II.
...
1
2
3
4
5
...