A Small-Molecule Modulator Affecting the Clock-Associated PSEUDO-RESPONSE REGULATOR 7 Amount.

Circadian clocks are biological timekeeping systems that coordinate genetic, metabolic and physiological behaviors with the external day-night cycle. The clock in plants relies on the transcriptional-translational feedback loops transcription-translation feedback loop (TTFL), consisting of transcription factors including PSUEDO-RESPONSE REGULATOR (PRR) proteins, plant lineage-specific transcriptional repressors. Here, we report that a novel synthetic small-molecule modulator, 5-(3,4-dichlorophenyl)-1-phenyl-1,7-dihydro-4H-pyrazolo[3,4-d] pyrimidine-4,6(5H)-dione (TU-892), affects the PRR7 protein amount. A clock reporter line of Arabidopsis was screened against the 10,000 small molecules in the Maybridge Hitfinder 10K chemical library. This screening identified TU-892 as a period-lengthening molecule. Gene expression analyses showed that TU-892 treatment upregulates CIRCADIAN CLOCK-ASSOCIATED 1 (CCA1) mRNA expression. TU-892 treatment reduced the amount of PRR7 protein, a transcriptional repressor of CCA1. Other PRR proteins including TIMING OF CAB EXPRESSION 1 were altered less by TU-892 treatment. TU-892-dependent CCA1 upregulation was attenuated in mutants impaired in PRR7. Collectively, TU-892 is a novel type of clock modulator that reduces the levels of PRR7 protein.

Phosphorylation of RNA Polymerase II by CDKC;2 Maintains the Arabidopsis Circadian Clock Period.

The circadian clock is an internal timekeeping system that governs about 24 h biological rhythms of a broad range of developmental and metabolic activities. The clocks in eukaryotes are thought to rely on lineage-specific transcriptional-translational feedback loops. However, the mechanisms underlying the basic transcriptional regulation events for clock function have not yet been fully explored. Here, through a combination of chemical biology and genetic approaches, we demonstrate that phosphorylation of RNA polymerase II by CYCLIN DEPENDENT KINASE C; 2 (CDKC;2) is required for maintaining the circadian period in Arabidopsis. Chemical screening identified BML-259, the inhibitor of mammalian CDK2/CDK5, as a compound lengthening the circadian period of Arabidopsis. Short-term BML-259 treatment resulted in decreased expression of most clock-associated genes. Development of a chemical probe followed by affinity proteomics revealed that BML-259 binds to CDKC;2. Loss-of-function mutations of cdkc;2 caused a long period phenotype. In vitro experiments demonstrated that the CDKC;2 immunocomplex phosphorylates the C-terminal domain of RNA polymerase II, and BML-259 inhibits this phosphorylation. Collectively, this study suggests that transcriptional activity maintained by CDKC;2 is required for proper period length, which is an essential feature of the circadian clock in Arabidopsis.

Casein kinase 1 family regulates PRR5 and TOC1 in the Arabidopsis circadian clock.

The circadian clock provides organisms with the ability to adapt to daily and seasonal cycles. Eukaryotic clocks mostly rely on lineage-specific transcriptional-translational feedback loops (TTFLs). Posttranslational modifications are also crucial for clock functions in fungi and animals, but the posttranslational modifications that affect the plant clock are less understood. Here, using chemical biology strategies, we show that the Arabidopsis CASEIN KINASE 1 LIKE (CKL) family is involved in posttranslational modification in the plant clock. Chemical screening demonstrated that an animal CDC7/CDK9 inhibitor, PHA767491, lengthens the Arabidopsis circadian period. Affinity proteomics using a chemical probe revealed that PHA767491 binds to and inhibits multiple CKL proteins, rather than CDC7/CDK9 homologs. Simultaneous knockdown of Arabidopsis CKL-encoding genes lengthened the circadian period. CKL4 phosphorylated transcriptional repressors PSEUDO-RESPONSE REGULATOR 5 (PRR5) and TIMING OF CAB EXPRESSION 1 (TOC1) in the TTFL. PHA767491 treatment resulted in accumulation of PRR5 and TOC1, accompanied by decreasing expression of PRR5- and TOC1-target genes. A prr5 toc1 double mutant was hyposensitive to PHA767491-induced period lengthening. Together, our results reveal posttranslational modification of transcriptional repressors in plant clock TTFL by CK1 family proteins, which also modulate nonplant circadian clocks.

A nationwide survey of common viral infections in childhood among patients with primary immunodeficiency diseases.

OBJECTIVES: Patients with primary immunodeficiency diseases (PID) are highly susceptible to various microorganisms. However, no population-based studies have been performed among common viral pathogens, such as respiratory syncytial virus (RSV), rotavirus (RV), varicella-zoster virus (VZV) and influenza virus (IV). The objective of this study was to reveal the clinical burden of these four infections among PID patients in Japan. METHODS: We conducted a nationwide survey by sending questionnaires to 898 hospitals with pediatric departments throughout Japan. RESULTS: Nine hundred ten PID patients from 621 hospitals were registered (response rate: 69.2%). Fifty-four of the patients were hospitalized due to these viral infections. The durations of hospitalization due to RSV and RV infections differed significantly in the PID patients with and without cellular immunodeficiency (12.0 vs 6.5 days, p = 0.041; and 14.0 vs 6.0 days, p = 0.031, respectively). There was no significant difference in the duration of hospitalization in PID patients with and without cellular immunodeficiency who were hospitalized with IV infections (7.3 vs 6.1 days, p = 0.53). CONCLUSIONS: Special attention should be paid to PID patients with compromised cellular immunity who present with RSV and RV infection due to their high risk for severe disease.

True fenestration of the anterior communicating artery diagnosed by magnetic resonance angiography.

Variations of the anterior cerebral artery-anterior communicating artery (ACoA) complex are common. Most are duplicated or partially duplicated ACoAs that are confused with fenestration of the ACoA. We report here an extremely rare case of true fenestration of the ACoA diagnosed by magnetic resonance angiography. Tiny true fenestrations of the ACoA may be overlooked easily by MR angiography. Partial maximum-intensity-projection image and volume-rendering image are useful in identifying true fenestration of the ACoA.

A functional single-nucleotide polymorphism in the human cytidine deaminase gene contributing to ara-C sensitivity.

To test the hypothesis that analyses of drug targets for polymorphism will help to establish gene-based information for the treatment of cancer patients, we investigated the functional single-nucleotide polymorphisms in the human cytidine deaminase (HDCA) gene. The cDNAs from 52 leukaemia/lymphoma samples and 169 control blood samples were direct-sequenced and analysed for the polymorphisms. Three different polymorphisms (A79C, G208A and T435C) were identified in the coding region of the HDCA gene and displayed allelic frequencies of 20.1%, 4.3% and 70.1%, respectively. No association with susceptibility to disease was observed. A novel polymorphism, G208A produced an alanine to threonine substitution (A70T) within the conserved catalytic domain. By introduction of the polymorphic HCDA genes into the yeast CDA-null mutants, the HCDA-70T showed 40% and 32% activity of prototype for cytidine and ara-C substrates, respectively (P < 0.01). The ara-C IC50 value of the yeast transformants carrying HCDA-70T was 757 +/- 33 micromol and was significantly lower (P < 0.01) than that of prototype (941 +/- 58 micromol). This study demonstrated a population characterized with 208A genotype for, which potentially leads one more sensitive to ara-C treatment than prototype. Accumulation of polymorphisms in the genes responsible for drug metabolism and determination of polymorphism-induced biological variations could provide the additional therapeutic strategies in risk-stratified protocols for the treatment of childhood malignancies.

CD8alpha alpha memory effector T cells descend directly from clonally expanded CD8alpha +beta high TCRalpha beta T cells in vivo.

Whereas most peripheral CD8(+) alphabeta T cells highly express CD8alphabeta heterodimer in healthy individuals, there is an increase of CD8alpha(+)beta(low) or CD8alphaalpha alphabeta T cells in HIV infection or Wiskott-Aldrich syndrome and after bone marrow transplantation. The significance of these uncommon cell populations is not well understood. There has been some question as to whether these subsets and CD8alpha(+)beta(high) cells belong to different ontogenic lineages or whether a fraction of CD8alpha(+)beta(high) cells have down-regulated CD8beta chain. Here we assessed clonality of CD8alphaalpha and CD8alpha(+)beta(low) alphabeta T cells as well as their phenotypic and functional characteristics. Deduced from surface antigens, cytotoxic granule constituents, and cytokine production, CD8alpha(+)beta(low) cells are exclusively composed of effector memory cells. CD8alphaalpha cells comprise effector memory cells and terminally differentiated CD45RO(-)CCR7(-) memory cells. T-cell receptor (TCR) Vbeta complementarity-determining region 3 (CDR3) spectratyping analysis and subsequent sequencing of CDR3 cDNA clones revealed polyclonality of CD8alpha(+)beta(high) cells and oligoclonality of CD8alpha(+)beta(low) and CD8alphaalpha cells. Importantly, some expanded clones within CD8alphaalpha cells were also identified within CD8alpha(+)beta(high) and CD8alpha(+)beta(low) subpopulations. Furthermore, signal-joint TCR rearrangement excision circles concentration was reduced with the loss of CD8beta expression. These results indicated that some specific CD8alpha(+)beta(high) alphabeta T cells expand clonally, differentiate, and simultaneously down-regulate CD8beta chain possibly by an antigen-driven mechanism. Provided that antigenic stimulation directly influences the emergence of CD8alphaalpha alphabeta T cells, these cells, which have been previously regarded as of extrathymic origin, may present new insights into the mechanisms of autoimmune diseases and immunodeficiencies, and also serve as a useful biomarker to evaluate the disease activities.