Exploring homeowner diffusion of yard care knowledge as one step toward improving urban ecosystems.

Urban ecosystems are increasingly influenced by residential yard care decisions. This had led researchers to focus on homeowner education programs when it comes to yard care. Typically, the success of programs designed to influence yard care is based on whether the target subject changes his or her behavior in a more environmentally conscious manner.

Fate of RNA polymerase II stalled at a cisplatin lesion.

Elongating RNA polymerase II blocked by DNA damage in the transcribed DNA strand is thought to initiate the transcription-coupled repair process. The objective of this study is to better understand the sequence of events that occurs during repair from the time RNA polymerase II first encounters the lesion. This study establishes that an immobilized DNA template containing a unique cisplatin lesion can serve as an in vitro substrate for both transcription and DNA repair.

Dephosphorylation of RNA polymerase II by CTD-phosphatase FCP1 is inhibited by phospho-CTD associating proteins.

Reversible phosphorylation of the repetitive C-terminal domain (CTD) of the largest RNA polymerase (RNAP) II subunit plays a key role in the progression of RNAP through the transcription cycle. The level of CTD phosphorylation is determined by multiple CTD kinases and a CTD phosphatase, FCP1. The phosphorylated CTD binds to a variety of proteins including the cis/trans peptidyl-prolyl isomerase (PPIase) Pin1 and enzymes involved in processing of the primary transcript such as the capping enzyme Hce1 and CA150, a nuclear factor implicated in transcription elongation.

The repetitive C-terminal domain of RNA polymerase II: multiple conformational states drive the transcription cycle.

RNA polymerase (RNAP) II is a complex multisubunit enzyme responsible for the synthesis of mRNA in eukaryotic cells. The largest subunit contains at its C-terminus a unique domain, designated the CTD, comprised of tandem repeats of the consensus sequence Tyr(1)Ser(2)Pro(3)Thr(4)Ser(5)Pro(6)Ser(7). This repeat occurs 52 times in mammalian RNAP II.

A novel RNA polymerase II C-terminal domain phosphatase that preferentially dephosphorylates serine 5.

The transcription and processing of pre-mRNA in eukaryotic cells are regulated in part by reversible phosphorylation of the C-terminal domain of the largest RNA polymerase (RNAP) II subunit. The CTD phosphatase, FCP1, catalyzes the dephosphorylation of RNAP II and is thought to play a major role in polymerase recycling. This study describes a family of small CTD phosphatases (SCPs) that preferentially catalyze the dephosphorylation of Ser5 within the consensus repeat.

Role of C-terminal domain phosphorylation in RNA polymerase II transcription through the nucleosome.

End-initiated transcription of a 256 base-pair (bp) template containing a single uniquely positioned nucleosome by yeast and calf thymus nuclear RNA polymerases II (pol II) was analyzed in vitro. The nucleosome-specific pausing pattern is similar to the pattern observed in the case of transcription of the same nucleosome by yeast RNA polymerase III. However, the pausing pattern is clearly different from the patterns observed previously during transcription by promoter-initiated and assembled pol II.

TFIIF-associating carboxyl-terminal domain phosphatase dephosphorylates phosphoserines 2 and 5 of RNA polymerase II.

The carboxyl-terminal domain (CTD) of the largest RNA polymerase (RNAP) II subunit undergoes reversible phosphorylation throughout the transcription cycle. The unphosphorylated form of RNAP II is referred to as IIA, whereas the hyperphosphorylated form is known as IIO. Phosphorylation occurs predominantly at serine 2 and serine 5 within the CTD heptapeptide repeat and has functional implications for RNAP II with respect to initiation, elongation, and transcription-coupled RNA processing.

CTD phosphatase: role in RNA polymerase II cycling and the regulation of transcript elongation.

The repetitive C-terminal domain (CTD) of the largest RNA polymerase II subunit plays a critical role in the regulation of gene expression. The activity of the CTD is dependent on its state of phosphorylation. A variety of CTD kinases act on RNA polymerase II at specific steps in the transcription cycle and preferentially phosphorylate distinct positions within the CTD consensus repeat.

Purification and characterization of the human elongator complex.

Human Elongator complex was purified to virtual homogeneity from HeLa cell extracts. The purified factor can exist in two forms: a six-subunit complex, holo-Elongator, which has histone acetyltransferase activity directed against histone H3 and H4, and a three-subunit core form, which does not have histone acetyltransferase activity despite containing the catalytic Elp3 subunit. Elongator is a component of early elongation complexes formed in HeLa nuclear extracts and can interact directly with RNA polymerase II in solution.

Transcription-independent RNA polymerase II dephosphorylation by the FCP1 carboxy-terminal domain phosphatase in Xenopus laevis early embryos.

The phosphorylation of the RNA polymerase II (RNAP II) carboxy-terminal domain (CTD) plays a key role in mRNA metabolism. The relative ratio of hyperphosphorylated RNAP II to hypophosphorylated RNAP II is determined by a dynamic equilibrium between CTD kinases and CTD phosphatase(s). The CTD is heavily phosphorylated in meiotic Xenopus laevis oocytes.

C-terminal domain phosphatase sensitivity of RNA polymerase II in early elongation complexes on the HIV-1 and adenovirus 2 major late templates.

The fate of RNA polymerase II in early elongation complexes is under the control of factors that regulate and respond to the phosphorylation state of the C-terminal domain (CTD). Phosphorylation of the CTD protects early elongation complexes from negative transcription elongation factors such as NELF, DSIF, and factor 2. To understand the relationship between transcript elongation and the sensitivity of RNA polymerase IIO to dephosphorylation, elongation complexes at defined positions on the Ad2-ML and human immunodeficiency virus type 1 (HIV-1) templates were purified, and their sensitivity to CTD phosphatase was determined.

Histidine-tagged ubiquitin substitutes for wild-type ubiquitin in Saccharomyces cerevisiae and facilitates isolation and identification of in vivo substrates of the ubiquitin pathway.

A general method for purification of any substrate of the ubiquitin pathway, the major eukaryotic proteolytic pathway, should utilize the common characteristic of covalent linkage of ubiquitin to substrate lysyl residues. The utility of a N-terminal histidine-tagged ubiquitin (HisUb) for in vivo conjugation and isolation of ubiquitinated proteins by metal chelation chromatography is conditioned by the requirement that HisUb conjugate to the same set of proteins as wild-type ubiquitin. Stringent in vivo tests with Saccharomyces cerevisiae strains expressing ubiquitins only from plasmids were performed to show that HisUb could substitute for wild-type ubiquitin.

The sensitivity of RNA polymerase II in elongation complexes to C-terminal domain phosphatase.

The phosphorylation state of the carboxyl-terminal domain (CTD) of the largest RNA polymerase (RNAP) II subunit plays an important role in the regulation of transcript elongation. This report examines the sensitivity of RNAP II to dephosphorylation by CTD phosphatase (CTDP) and addresses factors that regulate its sensitivity. The CTDP sensitivity of RNAP IIO in paused elongation complexes on a dC-tailed template does not significantly differ from that of free RNAP IIO.

Heat shock of HeLa cells inactivates a nuclear protein phosphatase specific for dephosphorylation of the C-terminal domain of RNA polymerase II.

Reversible phosphorylation of the C-terminal domain (CTD) of the largest RNA polymerase II (RNAP II) subunit plays a key role in gene expression. Stresses such as heat shock result in marked changes in CTD phosphorylation as well as in major alterations in gene expression. CTD kinases and CTD phosphatase(s) contribute in mediating differential CTD phosphory-lation.

Ultrastructural analysis of transcription and splicing in the cell nucleus after bromo-UTP microinjection.

In this study we demonstrate, at an ultrastructural level, the in situ distribution of heterogeneous nuclear RNA transcription sites after microinjection of 5-bromo-UTP (BrUTP) into the cytoplasm of living cells and subsequent postembedding immunoelectron microscopic visualization after different labeling periods. Moreover, immunocytochemical localization of several pre-mRNA transcription and processing factors has been carried out in the same cells. This high-resolution approach allowed us to reveal perichromatin regions as the most important sites of nucleoplasmic RNA transcription and the perichromatin fibrils (PFs) as in situ forms of nascent transcripts.

Regulation of carboxyl-terminal domain phosphatase by HIV-1 tat protein.

The phosphorylation state of the carboxyl-terminal domain (CTD) of RNA polymerase (RNAP) II is directly linked to the phase of transcription being carried out by the polymerase. Enzymes that affect CTD phosphorylation can thus play a major role in the regulation of transcription. A previously characterized HeLa CTD phosphatase has been shown to processively dephosphorylate RNAP II and to be stimulated by the 74-kDa subunit of TFIIF.

FCP1, the RAP74-interacting subunit of a human protein phosphatase that dephosphorylates the carboxyl-terminal domain of RNA polymerase IIO.

TFIIF (RAP30/74) is a general initiation factor that also increases the rate of elongation by RNA polymerase II. A two-hybrid screen for RAP74-interacting proteins produced cDNAs encoding FCP1a, a novel, ubiquitously expressed human protein that interacts with the carboxyl-terminal evolutionarily conserved domain of RAP74. Related cDNAs encoding FCP1b lack a carboxyl-terminal RAP74-binding domain of FCP1a.

Repression of host RNA polymerase II transcription by herpes simplex virus type 1.

Lytic infection of mammalian cells with herpes simplex virus type 1 (HSV-1) results in rapid repression of host gene expression and selective activation of the viral genome. This transformation in gene expression is thought to involve repression of host transcription and diversion of the host RNA polymerase (RNAP II) transcription machinery to the viral genome. However, the extent of virus-induced host transcription repression and the mechanisms responsible for these major shifts in transcription specificities have not been examined.

The photoactivated cross-linking of recombinant C-terminal domain to proteins in a HeLa cell transcription extract that comigrate with transcription factors IIE and IIF.

The C-terminal domain (CTD) of RNA polymerase II (RNAP II) is essential for the assembly of RNAP II into preinitiation complexes on some promoters such as the dihydrofolate reductase (DHFR) promoter. In addition, during the transition from a preinitiation complex to a stable elongation complex, the CTD becomes heavily phosphorylated. In this report, interactions involving the CTD have been examined by protein-protein cross-linking.

The activity of COOH-terminal domain phosphatase is regulated by a docking site on RNA polymerase II and by the general transcription factors IIF and IIB.

Each cycle of transcription appears to be associated with the reversible phosphorylation of the repetitive COOH-terminal domain (CTD) of the largest RNA polymerase (RNAP) II subunit. The dephosphorylation of RNAP II by CTD phosphatase, therefore, plays an important role in the transcription cycle. The following studies characterize the activity of HeLa cell CTD phosphatase with a special emphasis on the regulation of CTD phosphatase activity.

Phosphorylation of the C-terminal domain of RNA polymerase II.

The CTD has become a focal point in the analysis of RNAP II. The unusual properties of the CTD, including its unique structure and high level of phosphorylation, have stimulated interest in understanding the role this domain plays in the transcription of protein-coding genes. Research during the past ten years suggests that the CTD may function at multiple steps in the transcription cycle and that its involvement is promoter dependent.