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1.
Nucleic Acids Res ; 43(13): 6321-33, 2015 Jul 27.
Article in English | MEDLINE | ID: mdl-26068472

ABSTRACT

DNA double-strand breaks (DSBs) are the most severe type of DNA damage and are primarily repaired by non-homologous end joining (NHEJ) and homologous recombination (HR) in the G1 and S/G2 phase, respectively. Although CtBP-interacting protein (CtIP) is crucial in DNA end resection during HR following DSBs, little is known about how CtIP levels increase in an S phase-specific manner. Here, we show that Serpine mRNA binding protein 1 (SERBP1) regulates CtIP expression at the translational level in S phase. In response to camptothecin-mediated DNA DSBs, CHK1 and RPA2 phosphorylation, which are hallmarks of HR activation, was abrogated in SERBP1-depleted cells. We identified CtIP mRNA as a binding target of SERBP1 using RNA immunoprecipitation-coupled RNA sequencing, and confirmed SERBP1 binding to CtIP mRNA in S phase. SERBP1 depletion resulted in reduction of polysome-associated CtIP mRNA and concomitant loss of CtIP expression in S phase. These effects were reversed by reconstituting cells with wild-type SERBP1, but not by SERBP1 ΔRGG, an RNA binding defective mutant, suggesting regulation of CtIP translation by SERBP1 association with CtIP mRNA. These results indicate that SERBP1 affects HR-mediated DNA repair in response to DNA DSBs by regulation of CtIP translation in S phase.


Subject(s)
Carrier Proteins/biosynthesis , Gene Expression Regulation , Nuclear Proteins/biosynthesis , Protein Biosynthesis , RNA-Binding Proteins/metabolism , Recombinational DNA Repair , S Phase/genetics , 3' Untranslated Regions , Ataxia Telangiectasia Mutated Proteins/metabolism , Carrier Proteins/genetics , Carrier Proteins/metabolism , Cell Line , DNA Breaks, Double-Stranded , DNA Repair , Endodeoxyribonucleases , HeLa Cells , Humans , Nuclear Proteins/genetics , Nuclear Proteins/metabolism , RNA, Messenger/metabolism , RNA-Binding Proteins/physiology , Signal Transduction
2.
Electrophoresis ; 35(21-22): 3158-64, 2014 Nov.
Article in English | MEDLINE | ID: mdl-25142119

ABSTRACT

DNA degradation is a major obstacle in gaining an accurate profile with standard DNA typing technology. Although alternative genotyping strategies such as mini-STRs and SNPs have proven to be more successful in profiling degraded DNA, these approaches also have limitations. Here, we show that locus enrichment by hybridization of degraded genomic DNA with an STR locus-specific biotinylated oligonucleotide is a powerful approach to overcome problems in STR typing of highly degraded DNA. An experimental investigation of factors affecting the efficiency of this method indicates that the choice of primer and molar ratio of primers to genomic DNA are critical factors in improving enrichment of the STR locus before genotyping with multiplex kits. In addition, we find that indirect capture rather than direct capture with magnetic beads yields better enrichment efficiency for STR locus enrichments. Using these strategies, we demonstrate an improvement in STR typing of DNA from cultured cells damaged by exposure to sunlight or UV. We suggest that this approach could be applied to highly degraded forensic samples alone or in combination with mini-STRs.


Subject(s)
DNA Fingerprinting/methods , DNA/analysis , Forensic Genetics/methods , Tandem Repeat Sequences/genetics , DNA Fragmentation , Genomics , HeLa Cells , Humans , Magnets
3.
Biochem Biophys Res Commun ; 439(2): 252-7, 2013 Sep 20.
Article in English | MEDLINE | ID: mdl-23973487

ABSTRACT

Amyloid-ß (Aß) peptide is central to the development of brain pathology in Alzheimer disease (AD) patients. Association with receptors for advanced glycation end-products (RAGE) enables the transport of Aß peptide from circulating blood to human brain, and also causes the activation of the NF-κB signaling pathway. Here we show that two ß-strands of RAGE participate in the interaction with Aß peptide. Serial deletion analysis of the RAGE V domain indicates that the third and eighth ß-strands are required for interaction with Aß peptide. Site-directed mutagenesis of amino acids located in the third and eighth ß-strands abolish the interaction of RAGE with Aß peptide. Wild-type RAGE activates the NF-κB signaling pathway in response to Aß peptide treatment, while a RAGE mutant defective in Aß binding does not. Furthermore, use of peptide for the third ß-strand or a RAGE monoclonal antibody that targets the RAGE-Aß interaction interface inhibited transport of the Aß peptide across the blood brain barrier in a mice model. These results provide information crucial to the development of RAGE-derived therapeutic reagents for Alzheimer disease.


Subject(s)
Alzheimer Disease/metabolism , Amyloid beta-Peptides/metabolism , Blood-Brain Barrier/metabolism , Receptors, Immunologic/chemistry , Receptors, Immunologic/metabolism , Alzheimer Disease/immunology , Amino Acid Sequence , Animals , Antibodies, Monoclonal/immunology , Biological Transport , Gene Deletion , Humans , Male , Mice , Models, Molecular , Molecular Sequence Data , Mutagenesis, Site-Directed , NF-kappa B/immunology , Protein Interaction Maps , Protein Structure, Secondary , Protein Structure, Tertiary , Receptor for Advanced Glycation End Products , Receptors, Immunologic/genetics , Receptors, Immunologic/immunology
4.
Mol Cell ; 51(3): 374-85, 2013 Aug 08.
Article in English | MEDLINE | ID: mdl-23871434

ABSTRACT

WIP1 (wild-type p53-induced phosphatase 1) functions as a homeostatic regulator of the ataxia telangiectasia mutated (ATM)-mediated signaling pathway in response to ionizing radiation (IR). Here we identify homeodomain-interacting protein kinase 2 (HIPK2) as a protein kinase that targets WIP1 for phosphorylation and proteasomal degradation. In unstressed cells, WIP1 is constitutively phosphorylated by HIPK2 and maintained at a low level by proteasomal degradation. In response to IR, ATM-dependent AMPKα2-mediated HIPK2 phosphorylation promotes inhibition of WIP1 phosphorylation through dissociation of WIP1 from HIPK2, followed by stabilization of WIP1 for termination of the ATM-mediated double-strand break (DSB) signaling cascade. Notably, HIPK2 depletion impairs IR-induced γ-H2AX foci formation, cell-cycle checkpoint activation, and DNA repair signaling, and the survival rate of hipk2+/- mice upon γ-irradiation is markedly reduced compared to wild-type mice. Taken together, HIPK2 plays a critical role in the initiation of DSB repair signaling by controlling WIP1 levels in response to IR.


Subject(s)
Carrier Proteins/metabolism , DNA Damage/radiation effects , DNA Repair , Phosphoprotein Phosphatases/metabolism , Protein Serine-Threonine Kinases/metabolism , AMP-Activated Protein Kinases/metabolism , Animals , Cell Cycle Checkpoints , Cell Line, Tumor , DNA Damage/genetics , HEK293 Cells , HeLa Cells , Histones/metabolism , Humans , Mice , Mice, Transgenic , Phosphorylation , Protein Phosphatase 2C , Radiation, Ionizing , Signal Transduction , Ubiquitination
5.
EMBO Rep ; 13(2): 163-9, 2012 Feb 01.
Article in English | MEDLINE | ID: mdl-22173032

ABSTRACT

The Ras effector NORE1 is frequently silenced in primary adenocarcinomas, although the significance of this silencing for tumorigenesis is unclear. Here we show that NORE1 induces polyubiquitination and proteasomal degradation of oncoprotein HIPK1 by facilitating its interaction with the Mdm2 E3 ubiquitin ligase. Endogenous HIPK1 is stabilized in Nore1-deficient mouse embryonic fibroblasts, and depletion of HIPK1 in NORE1-silenced lung adenocarcinoma cells inhibits anchorage-independent cell growth and tumour formation in nude mice. These findings indicate that the control of HIPK1 stability by Mdm2-NORE1 has a major effect on cell behaviour, and epigenetic inactivation of NORE1 enables adenocarcinoma formation in vivo through HIPK1 stabilization.


Subject(s)
Adaptor Proteins, Signal Transducing/metabolism , Monomeric GTP-Binding Proteins/metabolism , Oncogene Proteins/metabolism , Protein Serine-Threonine Kinases/metabolism , Proteolysis , Proto-Oncogene Proteins c-mdm2/metabolism , ras Proteins/metabolism , Animals , Apoptosis Regulatory Proteins , Cell Line, Tumor , Cell Transformation, Neoplastic/metabolism , Cell Transformation, Neoplastic/pathology , Gene Knockdown Techniques , Humans , Mice , Polyubiquitin/metabolism , Protein Binding , Saccharomyces cerevisiae/metabolism , Ubiquitination
6.
Am J Hum Genet ; 87(4): 465-79, 2010 Oct 08.
Article in English | MEDLINE | ID: mdl-20887964

ABSTRACT

By defining the chromosomal breakpoint of a balanced t(10;12) translocation from a subject with Kallmann syndrome and scanning genes in its vicinity in unrelated hypogonadal subjects, we have identified WDR11 as a gene involved in human puberty. We found six patients with a total of five different heterozygous WDR11 missense mutations, including three alterations (A435T, R448Q, and H690Q) in WD domains important for ß propeller formation and protein-protein interaction. In addition, we discovered that WDR11 interacts with EMX1, a homeodomain transcription factor involved in the development of olfactory neurons, and that missense alterations reduce or abolish this interaction. Our findings suggest that impaired pubertal development in these patients results from a deficiency of productive WDR11 protein interaction.


Subject(s)
Chromosomes, Human, Pair 10/genetics , Homeodomain Proteins/genetics , Hypogonadism/genetics , Kallmann Syndrome/genetics , Membrane Proteins/genetics , Proto-Oncogene Proteins/genetics , Puberty/genetics , Transcription Factors/genetics , Translocation, Genetic/genetics , Adolescent , Animals , Humans , Immunoblotting , Immunohistochemistry , Immunoprecipitation , In Situ Hybridization , In Situ Hybridization, Fluorescence , Male , Membrane Proteins/metabolism , Mice , Microarray Analysis , Mutation, Missense/genetics , Polymorphism, Single Nucleotide/genetics , Proto-Oncogene Proteins/metabolism , Rats , Reverse Transcriptase Polymerase Chain Reaction , Two-Hybrid System Techniques , Zebrafish
7.
Biochem Biophys Res Commun ; 379(1): 160-5, 2009 Jan 30.
Article in English | MEDLINE | ID: mdl-19101520

ABSTRACT

Groucho is a corepressor that forms a macromolecular complex for its corepressor activity, in which HDAC1 is an essential component for the modulation of chromatin structure and transcriptional repression of target genes. Here, we show that Groucho is covalently conjugated with small ubiquitin-related modifier-1 (SUMO-1) in vitro and in vivo. SUMO conjugations of Groucho occur at four different lysine residues. Substitutions of all these residues abolished sumoylation of Groucho and inhibited its corepressor activity. In addition, Groucho corepressor activity was reduced by inhibition of SUMO-1 conjugation via Ubc9 knockdown through expression of short-hairpin RNA against Ubc9. Furthermore, interactions between Groucho and HDAC1 are enhanced by sumoylation of Groucho, which is mediated by the SUMO-interaction motif of HDAC1. Taken together, these findings indicate that Groucho sumoylation increases its corepressor activity by enhancing the recruitment of HDAC1 to Groucho corepressor complex.


Subject(s)
Basic Helix-Loop-Helix Transcription Factors/metabolism , Gene Expression Regulation , Histone Deacetylases/metabolism , Repressor Proteins/metabolism , SUMO-1 Protein/metabolism , Amino Acid Sequence , Animals , Basic Helix-Loop-Helix Transcription Factors/genetics , COS Cells , Chlorocebus aethiops , Gene Knockdown Techniques , Humans , Mice , Molecular Sequence Data , Repressor Proteins/genetics , Ubiquitin-Conjugating Enzymes/genetics , Ubiquitin-Conjugating Enzymes/metabolism
8.
J Biol Chem ; 283(8): 4682-9, 2008 Feb 22.
Article in English | MEDLINE | ID: mdl-18093972

ABSTRACT

Homeodomain-interacting protein kinase 2 (HIPK2) is a member of the nuclear protein kinase family, which induces both p53- and CtBP-mediated apoptosis. Levels of HIPK2 were increased by UV irradiation and cisplatin treatment, thereby implying the degradation of HIPK2 in cells under normal conditions. Here, we indicate that HIPK2 is ubiquitinated and degraded by the WD40-repeat/SOCS box protein WSB-1, a process that is blocked under DNA damage conditions. Yeast two-hybrid screening was conducted to identify the proteins that interact with HIPK2. WSB-1, an E3 ubiquitin ligase, was characterized as an HIPK2-interacting protein. The coexpression of WSB-1 resulted in the degradation of HIPK2 via its C-terminal region. Domain analysis of WSB-1 showed that WD40-repeats and the SOCS box were required for its interaction with and degradation of HIPK2, respectively. In support of the degradation of HIPK2 by WSB-1, HIPK2 was polyubiquitinated by WSB-1 in vitro and in vivo. The knockdown of endogenous WSB-1 with the expression of short hairpin RNA against WSB-1 increases the stability of endogenous HIPK2 and resulted in the accumulation of HIPK2. The ubiquitination and degradation of HIPK2 by WSB-1 was inhibited completely via the administration of DNA damage reagents, including Adriamycin and cisplatin. These findings effectively illustrate the regulatory mechanisms by which HIPK2 is maintained at a low level, by WSB-1 in cells under normal conditions, and stabilized by genotoxic stresses.


Subject(s)
Carrier Proteins/metabolism , Protein Processing, Post-Translational/physiology , Protein Serine-Threonine Kinases/metabolism , Proteins/metabolism , Ubiquitination/physiology , Alcohol Oxidoreductases/genetics , Alcohol Oxidoreductases/metabolism , Antibiotics, Antineoplastic/pharmacology , Apoptosis/drug effects , Apoptosis/physiology , Apoptosis/radiation effects , Carrier Proteins/genetics , Cell Line , Cisplatin/pharmacology , DNA Damage/drug effects , DNA Damage/physiology , DNA Damage/radiation effects , DNA-Binding Proteins/genetics , DNA-Binding Proteins/metabolism , Doxorubicin/pharmacology , Humans , Intracellular Signaling Peptides and Proteins , Protein Processing, Post-Translational/drug effects , Protein Processing, Post-Translational/radiation effects , Protein Serine-Threonine Kinases/genetics , Protein Structure, Tertiary/physiology , Proteins/genetics , Tumor Suppressor Protein p53/genetics , Tumor Suppressor Protein p53/metabolism , Ubiquitination/drug effects , Ubiquitination/radiation effects , Ultraviolet Rays
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