Direct Interaction between Nucleosome Assembly Protein 1 and the Papillomavirus E2 Proteins Involved in Activation of Transcription

Institute of Virology, University of Cologne, Köln, North Rhine-Westphalia, Germany
Molecular and Cellular Biology (Impact Factor: 4.78). 04/2004; 24(5):2153-68. DOI: 10.1128/MCB.24.5.2153-2168.2004
Source: PubMed


Using a yeast two-hybrid screen, we identified human nucleosome assembly protein 1 (hNAP-1) as a protein interacting with
the activation domain of the transcriptional activator encoded by papillomaviruses (PVs), the E2 protein. We show that the
interaction between E2 and hNAP-1 is direct and not merely mediated by the transcriptional coactivator p300, which is bound
by both proteins. Coexpression of hNAP-1 strongly enhances activation by E2, indicating a functional interaction as well.
E2 binds to at least two separate domains within hNAP-1, one within the C terminus and an internal domain. The binding of
E2 to hNAP-1 is necessary for cooperativity between the factors. Moreover, the N-terminal 91 amino acids are crucial for the
transcriptional activity of hNAP-1, since deletion mutants lacking this N-terminal portion fail to cooperate with E2. We provide
evidence that hNAP-1, E2, and p300 can form a ternary complex efficient in the activation of transcription. We also show that
p53 directly interacts with hNAP-1, indicating that transcriptional activators in addition to PV E2 interact with hNAP-1.
These results suggest that the binding of sequence-specific DNA binding proteins to hNAP-1 may be an important step contributing
to the activation of transcription.

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    • "Our finding of TSPYL2 regulating the transcription of Grin2a is novel. As there are multiple reports of direct interactions between NAPs and CBP or p30067833, recruitment of TSPYL2 to the various promoters by transcription regulators such as CASK, p300 and CBP may be a general mechanism. In return, TSPYL2 will help to anchor the transcriptional complex to chromatin through its binding to histone. "
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    ABSTRACT: TSPYL2 is an X-linked gene encoding a nucleosome assembly protein. TSPYL2 interacts with calmodulin-associated serine/threonine kinase, which is implicated in X-linked mental retardation. As nucleosome assembly and chromatin remodeling are important in transcriptional regulation and neuronal function, we addressed the importance of TSPYL2 through analyzing Tspyl2 loss-of-function mice. We detected down-regulation of N-methyl-D-aspartate receptor subunits 2A and 2B (GluN2A and GluN2B) in the mutant hippocampus. Evidence from luciferase reporter assays and chromatin immunoprecipitation supported that TSPYL2 regulated the expression of Grin2a and Grin2b, the genes encoding GluN2A and GluN2B. We also detected an interaction between TSPYL2 and CBP, indicating that TSPYL2 may activate gene expression through binding CBP. In terms of functional outcome, Tspyl2 loss-of-function impaired long-term potentiation at hippocampal Schaffer collateral-CA1 synapses. Moreover, mutant mice showed a deficit in fear learning and memory. We conclude that TSPYL2 contributes to cognitive variability through regulating the expression of Grin2a and Grin2b.
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    • "The M2 FLAG antibody was from Sigma-Aldrich, the anti-HA-antibody from Roche, the anti-actin antibody from Santa Cruz, and antibodies against IKKα and IKKβ were from Cell Signaling. Preparation of whole cell extracts and co-immunoprecipitations were conducted as described previously [36]. Dephosphorylation reactions were performed with λ-phosphatase (Santa Cruz) according to the manufacturer’s protocol. "
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    Preview · Article · Sep 2013 · PLoS ONE
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    • "NAP1L1 is primarily involved in replication-coupled nucleosome assembly by mediating the incorporation of histones H2A-H2B dimers in nucleosomes. Its direct binding to E2 from genotypes 5, 8 and 18 has been shown to enhance their transcriptional activation capacities [34], though this interaction might primarily impact on the replication activating functions of E2. On the other hand, the SWI/SNF chromatin remodeling complex was recently shown to enhance HPV18 E2-dependant transcription through direct binding of the core component hSNF5 to E2 [33]. "
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