Germinal center-associated nuclear protein (GANP) has a phosphorylation-dependent DNA-primase activity that is up-regulated in germinal center regions

Kuwahara, K.; Tomiyasu, Shinjirou; Fujimura, Satoru; Nomura, Kazumi; Xing, Yan; Nishiyama, N.; Ogawa, Michio; Imajoh‐Ohmi, Shinobu; Izuta, Shunji; Sakaguchi, Nobuo

doi:10.1073/pnas.181335698

Cited by 36 publications

(55 citation statements)

References 30 publications

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“…A 210-kDa germinal center-associated DNA primase (GANP) protein, bearing RNA-primase and minichromosome maintenance (MCM)3-binding activities, is up-regulated in GC B cells upon immunization with TD-Ag in vivo and is induced by the stimulation to BCR and CD40 in vitro (3,4). The mutant mouse with ganp gene knockout B cells (B-ganp Ϫ/Ϫ ) has a severe defect in mounting high-affinity Ab responses to TD-Ag (5), suggesting that GANP is required for generation of high-affinity Ab in response to TD-Ag in vivo.…”

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confidence: 99%

Generation of High-Affinity Antibody against T Cell-Dependent Antigen in the Ganp Gene-Transgenic Mouse

Sakaguchi

Kimura²,

Matsushita³

et al. 2005

The Journal of Immunology

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Generation of high-affinity Ab is impaired in mice lacking germinal center-associated DNA primase (GANP) in B cells. In this study, we examined the effect of its overexpression in ganp transgenic C57BL/6 mice (GanpTg). GanpTg displayed normal phenotype in B cell development, serum Ig levels, and responses against T cell-independent Ag; however, it generated the Ab with much higher affinity against nitrophenyl-chicken gammaglobulin in comparison with C57BL/6. To further examine the affinity increase, we established hybridomas producing high-affinity mAbs and compared their affinities using BIAcore. C57BL/6 generated high-affinity anti-nitrophenyl mAbs (KD ∼ 2.50 × 10−7 M) of IgG1/λ1 and contained the VH186.2 region with W33L mutation. GanpTg generated much higher affinity (KD > 1.57 × 10−9 M) by usage of VH186.2 as well as noncanonical VH7183 regions. GanpTg also generated exceptionally high-affinity anti-HIV-1 (V3 peptide) mAbs (KD > 9.90 × 10−11 M) with neutralizing activity. These results demonstrated that GANP is involved in V region alteration generating high-affinity Ab.

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confidence: 99%

Generation of High-Affinity Antibody against T Cell-Dependent Antigen in the Ganp Gene-Transgenic Mouse

Sakaguchi

Kimura²,

Matsushita³

et al. 2005

The Journal of Immunology

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“…Stimulation-dependent Induction of ganp Promoter-GANP protein expression in resting primary spleen cells are markedly increased by treatment with anti-CD40 mAb (15)(16)(17). Because the ganp promoter potentially regulates the B cell by stimulation in vitro with anti-CD40 mAb, we examined whether this promoter region with the PU.1 site is a target of anti-CD40 signaling.…”

Section: Fig 2 Deletion Analysis Of the Mouse Ganp Promotermentioning

confidence: 99%

“…These results suggest that the PU.1 site in the promoter region is involved in the anti-CD40-induced up-regulation of the ganp gene. DISCUSSION GANP is a new member of RNA/DNA primase that associates with the DNA-helicase complex of MCMs, and interestingly both the expression and the activity of DNA primase are induced in antigen-driven B cells in GCs (17). The role of GANP may be more diverse; GANP may be involved in DNA replica- FIG.…”

Section: Fig 2 Deletion Analysis Of the Mouse Ganp Promotermentioning

confidence: 99%

“…Recently, a mAb identified a differentiation antigen named GC-associated DNA primase (GANP) that is up-regulated selectively in GC-B cells (15)(16)(17). GANP protein is hardly detectable in normal lymphoid tissues and organs but is up-regulated in GCs of antigen-immunized spleen and lymph nodes.…”

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“…The MCM complex required for DNA replication is composed of at least six identified components known as MCM2, 3, 4, 5, 6, and 7; some of which are phosphorylated during cell cycling (23)(24)(25). GANP also bears a DNA primase activity that is inducible by phosphorylation of Ser 502 of GANP (17). The findings regarding the structure and associated components of GANP suggest a role for GANP in the proliferation and DNA replication of lymphoid lineage cells.…”

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PU.1 Is Involved in the Regulation of B Lineage-associated and Developmental Stage-dependent Expression of the Germinal Center-associated DNA Primase GANP

A.M.El-Gazzar¹,

Maeda²,

Nomiyama

et al. 2001

Journal of Biological Chemistry

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Germinal center-associated DNA primase (GANP) associated with MCM3 of the DNA replication complex is up-regulated selectively in germinal center B cells. We studied promoter activity of the 5 region involved in the developmental stage-dependent expression in B lineage cells by luciferase reporter assay. Selective regulation of ganp expression was observed in the ؊737-bp promoter region in B and plasma cell lines but was significantly low in pre-B and T cell lines. The deletion constructs displayed a gap decrease after shortening the region from ؊134 to ؊108 bp. Further narrowing suggested the involvement of the PU.1 consensus sequence at ؊126 bp by electrophoretic mobility shift assay. The protein component PU.1 complex is not inhibited with mutated probes at the consensus site but is inhibited with the known PU.1 probe of CD72 and with anti-PU.1 antibody. Moreover, introduction of PU.1 cDNA enhanced the reporter gene activity in a dose-dependent manner in B cells, whereas the reporter construct with the mutated PU.1 site did not respond. Anti-CD40 stimulation induced the reporter activity with a 100% increase, which is not observed with the PU.1-mutated reporter construct. These results demonstrate that the germinal center-associated DNA primase expression is partly regulated by the transcription factor PU.1 expressed in B lineage cells.Immunization with T cell-dependent antigen induces proliferation of specific B cell clones in the germinal center (GC)

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Selective cell death of p53-insufficient cancer cells is induced by knockdown of the mRNA export molecule GANP

Phimsen¹,

Kuwahara²,

Nakaya³

et al. 2012

Apoptosis

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Cancer cells often contain p53 abnormalities that impair cell-cycle checkpoint progression and cause resistance to various anti-cancer treatments. DNA damage occurs at actively transcribed genes during G1-phase in yeast cells that have a deficient mRNA export capacity. Here, we show that germinal center-associated nuclear protein (GANP), a homologue of yeast Sac3 that is involved in mRNA export, is indispensable for ensuring the stability of human genomic DNA and that GANP knockdown causes apoptosis and necrosis of p53-insufficient cancer cells. Ganp small interfering RNA (siGanp)-induced DNA damage, accompanied by a decrease in the number of cells in S-phase, caused late apoptosis and necrosis in p53-insufficient cancer cells through both caspase-dependent and -independent mechanisms. siGanp effectively induced DNA damage leading to cell death in p53-insufficient cancer cells in vitro and protect the growth of cancer cells transplanted into immunocompromized mice, suggesting that siGanp has potential as a selective treatment for p53-insufficient cancer cells.

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Germinal center-associated nuclear protein (GANP) has a phosphorylation-dependent DNA-primase activity that is up-regulated in germinal center regions

Cited by 36 publications

References 30 publications

Generation of High-Affinity Antibody against T Cell-Dependent Antigen in the Ganp Gene-Transgenic Mouse

Generation of High-Affinity Antibody against T Cell-Dependent Antigen in the Ganp Gene-Transgenic Mouse

PU.1 Is Involved in the Regulation of B Lineage-associated and Developmental Stage-dependent Expression of the Germinal Center-associated DNA Primase GANP

Selective cell death of p53-insufficient cancer cells is induced by knockdown of the mRNA export molecule GANP

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