Rpa43 and its partners in the yeast RNA polymerase I transcription complex.

An Rpa43/Rpa14 stalk protrudes from RNA polymerase I (RNAPI), with homology to Rpb7/Rpb4 (RNAPII), Rpc25/Rpc17 (RNAPIII) and RpoE/RpoF (archaea). In fungi and vertebrates, Rpa43 contains hydrophilic domains forming about half of its size, but these domains lack in Schizosaccharomyces pombe and most other eukaryote lineages. In Saccharomyces cerevisiae, they can be lost with little or no growth effect, as shown by deletion mapping and by domain swapping with fission yeast, but genetically interact with rpa12Δ, rpa34Δ or rpa49Δ, lacking non-essential subunits important for transcript elongation.

The route of immunization with adenoviral vaccine influences the recruitment of cytotoxic T lymphocytes in the lung that provide potent protection from influenza A virus.

Virus-specific cytotoxic T lymphocytes (CTLs) in the lung are considered to confer protection from respiratory viruses. Several groups demonstrated that the route of priming was likely to have an implication for the trafficking of antigen-specific CTLs. Therefore, we investigated whether the route of immunization with adenoviral vaccine influenced the recruitment of virus-specific CTLs in the lung that should provide potent protection from influenza A virus.

Saccharomyces cerevisiae protein phosphatase Ppz1 and protein kinases Sat4 and Hal5 are involved in the control of subcellular localization of Gln3 by likely regulating its phosphorylation state.

A Saccharomyces cerevisiae mutant lacking PPZ1, encoding a serine/threonine protein phosphatase (PPase), is caffeine-sensitive. To clarify the function of Ppz1 in resistance to caffeine, we attempted systematically to identify protein kinase (PKase) whose disruption lead to suppression of caffeine sensitive phenotype of the ∆ppz1 disruptant since disruption of PPZ1 might cause caffeine sensitivity by increasing its phosphorylated substrates and we presumed that disruption of genes for PKase sharing the substrate with Ppz1 could restore the resistance through bypassing necessity for dephosphorylation of substrates. Among the 102 viable pkase disruptions, disruption of either SAT4 or HAL5 suppressed the caffeine sensitivity phenotype and increased expression of ENA1, encoding a P-type ATPase of the ∆ppz1 disruptant.

Galactose transporters discriminate steric anomers at the cell surface in yeast.

Aldose-1-epimerase or mutarotase (EC 5.1.3.

Two RNA polymerase I subunits control the binding and release of Rrn3 during transcription.

Rpa34 and Rpa49 are nonessential subunits of RNA polymerase I, conserved in species from Saccharomyces cerevisiae and Schizosaccharomyces pombe to humans. Rpa34 bound an N-terminal region of Rpa49 in a two-hybrid assay and was lost from RNA polymerase in an rpa49 mutant lacking this Rpa34-binding domain, whereas rpa34Delta weakened the binding of Rpa49 to RNA polymerase. rpa34Delta mutants were caffeine sensitive, and the rpa34Delta mutation was lethal in a top1Delta mutant and in rpa14Delta, rpa135(L656P), and rpa135(D395N) RNA polymerase mutants.

The fission yeast protein Ker1p is an ortholog of RNA polymerase I subunit A14 in Saccharomyces cerevisiae and is required for stable association of Rrn3p and RPA21 in RNA polymerase I.

A heterodimer formed by the A14 and A43 subunits of RNA polymerase (pol) I in Saccharomyces cerevisiae is proposed to correspond to the Rpb4/Rpb7 and C17/C25 heterodimers in pol II and pol III, respectively, and to play a role(s) in the recruitment of pol I to the promoter. However, the question of whether the A14/A43 heterodimer is conserved in eukaryotes other than S. cerevisiae remains unanswered, although both Rpb4/Rpb7 and C17/C25 are conserved from yeast to human.

Essential role of p38 mitogen-activated protein kinase in cathepsin K gene expression during osteoclastogenesis through association of NFATc1 and PU.1.

The receptor activator of NF-kappaB ligand (RANKL) induces various osteoclast-specific marker genes during osteoclast differentiation mediated by mitogen-activated protein (MAP) kinase cascades. However, the results of transcriptional programming of an osteoclast-specific cathepsin K gene are inconclusive. Here we report the regulatory mechanisms of RANKL-induced cathepsin K gene expression during osteoclastogenesis in a p38 MAP kinase-dependent manner.

Transcriptional coactivator PC4 stimulates promoter escape and facilitates transcriptional synergy by GAL4-VP16.

Positive cofactor 4 (PC4) is a coactivator that strongly augments transcription by various activators, presumably by facilitating the assembly of the preinitiation complex (PIC). However, our previous observation of stimulation of promoter escape in GAL4-VP16-dependent transcription in the presence of PC4 suggested a possible role for PC4 in this step. Here, we performed quantitative analyses of the stimulatory effects of PC4 on initiation, promoter escape, and elongation in GAL4-VP16-dependent transcription and found that PC4 possesses the ability to stimulate promoter escape in response to GAL4-VP16 in addition to its previously demonstrated effect on PIC assembly.

Multiple protein-protein interactions by RNA polymerase I-associated factor PAF49 and role of PAF49 in rRNA transcription.

We previously demonstrated the critical role of RNA polymerase I (Pol I)-associated factor PAF53 in mammalian rRNA transcription. Here, we report the isolation and characterization of another Pol I-associated factor, PAF49. Mouse PAF49 shows striking homology to the human nucleolar protein ASE-1, so that they are considered orthologues.

The fission yeast RPA51 is a functional homolog of the budding yeast A49 subunit of RNA polymerase I and required for maximizing transcription of ribosomal DNA.

Saccharomyces cerevisiae A49 and mouse PAF53 are subunits specific to RNA polymerase I (Pol I) in eukaryotes. It has been known that Pol I without A49 or PAF53 maintains non-specific transcription activities but a molecular role(s) of A49 (and PAF53) remains totally unknown. We studied the fission yeast gene encoding a protein of 415 amino acids exhibiting 30% and 19% identities to A49 and PAF53, respectively.

Alleviation of PC4-mediated transcriptional repression by the ERCC3 helicase activity of general transcription factor TFIIH.

Positive cofactor 4 (PC4), originally identified as a transcriptional coactivator, possesses the ability to suppress promoter-driven as well as nonspecific transcription via its DNA binding activity. Previous studies showed that the repressive activity of PC4 on promoter-driven transcription is alleviated by transcription factor TFIIH, possibly through one of its enzymatic activities. Using recombinant TFIIH, we have analyzed the role of TFIIH for alleviating PC4-mediated transcriptional repression and determined that the excision repair cross complementing (ERCC3) helicase activity of TFIIH is the enzymatic activity that alleviates PC4-mediated repression via beta-gamma bond hydrolysis of ATP.

The fission yeast RPA21 subunit of RNA polymerase I: an evolutionarily conserved subunit interacting with ribosomal DNA (rDNA) transcription factor Rrn3p for recruitment to rDNA promoter.

Recruitment of RNA polymerases to the cognate promoter is a key step for the transcription initiation of specific genes in eukaryotes. Recently, RNA polymerase I (pol I) of Saccharomyces cerevisiae was shown to be recruited to the rDNA promoter via interaction between Rrn3p, a conserved transcription factor for rDNA, and A43, a subunit specific to pol I. The question of whether a similar interaction for pol I recruitment is conserved in other eukaryotes remains to be answered.

The regulatory role for the ERCC3 helicase of general transcription factor TFIIH during promoter escape in transcriptional activation.

Eukaryotic transcriptional activators have been proposed to function, for the most part, by promoting the assembly of preinitiation complex through the recruitment of the RNA polymerase II transcriptional machinery to the promoter. Previous studies have shown that transcriptional activation is critically dependent on transcription factor IIH (TFIIH), which functions during promoter opening and promoter escape, the steps following preinitiation complex assembly. Here we have analyzed the role of TFIIH in transcriptional activation and show that the excision repair cross-complementing (ERCC) 3 helicase activity of TFIIH plays a regulatory role to stimulate promoter escape in activated transcription.