RNA Polymerase II CTD phosphatase Rtr1 fine-tunes transcription termination.

RNA Polymerase II (RNAPII) transcription termination is regulated by the phosphorylation status of the C-terminal domain (CTD). The phosphatase Rtr1 has been shown to regulate serine 5 phosphorylation on the CTD; however, its role in the regulation of RNAPII termination has not been explored. As a consequence of RTR1 deletion, interactions within the termination machinery and between the termination machinery and RNAPII were altered as quantified by Disruption-Compensation (DisCo) network analysis.

Phosphatase Rtr1 Regulates Global Levels of Serine 5 RNA Polymerase II C-Terminal Domain Phosphorylation and Cotranscriptional Histone Methylation.

In eukaryotes, the C-terminal domain (CTD) of Rpb1 contains a heptapeptide repeat sequence of (Y1S2P3T4S5P6S7)n that undergoes reversible phosphorylation through the opposing action of kinases and phosphatases. Rtr1 is a conserved protein that colocalizes with RNA polymerase II (RNAPII) and has been shown to be important for the transition from elongation to termination during transcription by removing RNAPII CTD serine 5 phosphorylation (Ser5-P) at a selection of target genes. In this study, we show that Rtr1 is a global regulator of the CTD code with deletion of RTR1 causing genome-wide changes in Ser5-P CTD phosphorylation and cotranscriptional histone H3 lysine 36 trimethylation (H3K36me3).

Quantitative Analysis of Dynamic Protein Interactions during Transcription Reveals a Role for Casein Kinase II in Polymerase-associated Factor (PAF) Complex Phosphorylation and Regulation of Histone H2B Monoubiquitylation.

Using affinity purification MS approaches, we have identified a novel role for casein kinase II (CKII) in the modification of the polymerase associated factor complex (PAF-C). Our data indicate that the facilitates chromatin transcription complex (FACT) interacts with CKII and may facilitate PAF complex phosphorylation. Posttranslational modification analysis of affinity-isolated PAF-C shows extensive CKII phosphorylation of all five subunits of PAF-C, although CKII subunits were not detected as interacting partners.

RPRD1A and RPRD1B are human RNA polymerase II C-terminal domain scaffolds for Ser5 dephosphorylation.

The RNA polymerase II (RNAPII) C-terminal domain (CTD) heptapeptide repeats (1-YSPTSPS-7) undergo dynamic phosphorylation and dephosphorylation during the transcription cycle to recruit factors that regulate transcription, RNA processing and chromatin modification. We show here that RPRD1A and RPRD1B form homodimers and heterodimers through their coiled-coil domains and interact preferentially via CTD-interaction domains (CIDs) with RNAPII CTD repeats phosphorylated at S2 and S7. Crystal structures of the RPRD1A, RPRD1B and RPRD2 CIDs, alone and in complex with RNAPII CTD phosphoisoforms, elucidate the molecular basis of CTD recognition.

The interactome of the atypical phosphatase Rtr1 in Saccharomyces cerevisiae.

The phosphatase Rtr1 has been implicated in dephosphorylation of the RNA Polymerase II (RNAPII) C-terminal domain (CTD) during transcription elongation and in regulation of nuclear import of RNAPII. Although it has been shown that Rtr1 interacts with RNAPII in yeast and humans, the specific mechanisms that underlie Rtr1 recruitment to RNAPII have not been elucidated. To address this, we have performed an in-depth proteomic analysis of Rtr1 interacting proteins in yeast.

Expression and purification of functional human glycogen synthase-1 (hGYS1) in insect cells.

We have successfully expressed and purified active human glycogen synthase-1 (hGYS1). Successful production of the recombinant hGYS1 protein was achieved by co-expression of hGYS1 and rabbit glycogenin (rGYG1) using the MultiBac baculovirus expression system (BEVS). Functional measurements of activity ratios of hGYS1 in the absence and presence of glucose-6-phosphate and treatment with phosphatase indicate that the expressed protein is heavily phosphorylated.

Quantitative proteomics demonstrates that the RNA polymerase II subunits Rpb4 and Rpb7 dissociate during transcriptional elongation.

Eukaryotic RNA polymerase II (RNAPII) is a 12-subunit enzyme that is responsible for the transcription of messenger RNA. Two of the subunits of RNA polymerase II, Rpb4 and Rpb7, have been shown to dissociate from the enzyme under a number of specific laboratory conditions. However, a biological context for the dissociation of Rpb4 and Rpb7 has not been identified.

The gas-phase ligand exchange reactions of cobalt and zinc acetylacetonate, hexafluoroacetylacetonate, and trifluorotrimethylacetylacetonate complexes.

The gas-phase ligand exchange reactions between Co(II) and Zn(II) complexes containing the acetylacetonate (acac), hexafluoroacetylacetonate (hfac), and trifluorotrimethylacetylacetonate (tftm) ligands were investigated using a triple quadrupole mass spectrometer. The gas-phase mixed ligand products of [Cu(acac)(tftm)](+), [Ni(acac)(tftm)](+), [Cu(hfac)(tftm)](+), and [Ni(hfac)(tftm)](+) were formed following the co-sublimation of either homo-metal or hetero-metal precursors and are reported herein for the first time. The fragmentation patterns of these mixed ligand species along with those of Cu(tftm)(2) and Ni(tftm)(2) are also presented.

The gas-phase ligand exchange of copper and nickel acetylacetonate, hexafluoroacetylacetonate and trifluorotrimethylacetylacetonate complexes.

The gas-phase ligand-exchange reactions between Cu(II) and Ni(II) complexes containing the acetylacetonate (acac), hexafluoroacetylacetonate (hfac), and trifluorotrimethylacetylacetonate (tftm) ligands were investigated using a triple quadrupole mass spectrometer. The gas-phase mixed-ligand products of [Cu(acac)(tftm)](+), [Ni(acac)(tftm)](+), [Cu(hfac)(tftm)](+), and [Ni(hfac)(tftm)](+) were formed following the co-sublimation of either homo-metal or hetero-metal precursors. The gas-phase formation of [Cu(acac)(tftm)](+), [Cu(hfac)(tftm)](+), [Ni(acac)(tftm)](+), and [Ni(hfac)(tftm)](+) complexes is reported herein for the first time.

cis-[Aqua/methanol(0.45/1.55)](1,1,1-trifluoro-5,5-dimethyl-hexane-2,4-dionato)nickel(II)-cis-[aqua/methanol(1.49/0.51)](1,1,1-trifluoro-5,5-dimethyl-hexane-2,4-dionato)nickel(II) (1/1).

The title compound, [Ni(C(8)H(10)F(3)O(2))(2)(CH(4)O)(1.55)(H(2)O)(0.45)][Ni(C(8)H(10)F(3)O(2))(2)(CH(4)O)(0.

Bis[μ-pentane-2,4-dionato(1-)]bis-{aqua-[1,1,1,5,5,5-hexa-fluoro-pentane-2,4-dionato(1-)]cobalt(II)}.

The title complex, [Co(2)(C(5)HF(6)O(2))(2)(C(5)H(7)O(2))(2)(H(2)O)(2)], is centrosymmetric with a crystallographic inversion center in the middle of the mol-ecule. The octa-hedrally coordinated Co(II) atoms are bridged by two chelating acetyl-acetonate (acac) ligands and two more electron-poor 1,1,1,5,5,5-hexa-fluoro-pentane-2,4-dionato (hfac) ligands are bonded terminally in a solely chelating manner. The coordinated water mol-ecules form inter-molecular O-H⋯O hydrogen bonds with electron-rich acac O atoms of neighboring mol-ecules, leading to strings of mol-ecules along the a axis.

trans-Dimethano-lbis(1,1,1-trifluoro-5,5-dimethyl-hexane-2,4-dionato)zinc(II).

The title compound, [Zn(C(8)H(10)F(3)O(2))(2)(CH(4)O)(2)], is a dimethanol coordinated zinc complex with the acetyl acetonate derivative 1,1,1-trifluoro-5,5-dimethyl-hexane-2,4-dionate. The bis--β-diketonate complex, which is isostructural with its Co analogue, is located on a crystallographic inversion center. The complex is octa-hedral with basically no distortion, and the methanol mol-ecules are in trans positions with respect to one another.