Mapping of the regions implicated in nuclear localization of multi-functional DNA repair endonuclease XPF-ERCC1.

The structure-specific endonuclease XPF-ERCC1 is a multi-functional heterodimer that participates in a variety of DNA repair mechanisms for maintaining genome integrity. Both subunits contain C-terminal tandem helix-hairpin-helix (HhH2 ) domains, which are necessary for not only their dimerization but also enzymatic activity as well as protein stability. However, the interdependency of both subunits in their nuclear localization remains poorly understood. In this study, we have analyzed the region(s) that affects the subcellular localization of XPF and ERCC1 using various deletion mutants. We first identified the nuclear localization signal (NLS) in XPF, which was essential for its nuclear localization under the ERCC1-free condition, but dispensable in the presence of ERCC1 (probably as XPF-ERCC1 heterodimer). Interestingly, in the NLS-independent and ERCC1-dependent XPF nuclear localization, the physical interaction between XPF and ERCC1 via C-terminal HhH2 domains was not needed. Instead, the amino acid regions 311-469 of XPF and 216-260 of ERCC1 are required for the nuclear localization. Furthermore, we found that the 311-469 region of XPF interacts with ERCC1 in a co-immunoprecipitation assay. These results suggest that the nuclear localization of XPF-ERCC1 heterodimer is regulated at multiple levels in an interdependent manner.

Effectiveness of Mindfulness-Based Cognitive Therapy With Follow-Up Sessions for Pharmacotherapy-Refractory Anxiety Disorders: Protocol for a Feasibility Randomized Controlled Trial.

BACKGROUND: Augmented mindfulness-based cognitive therapy (MBCT) with treatment as usual (mainly pharmacotherapy) is reported to be effective after treatment for anxiety disorders. However, whether its effectiveness persists in the long term is unclear. OBJECTIVE: This study aims to examine the feasibility, acceptability, and effectiveness of a follow-up program by conducting a feasibility randomized controlled trial (RCT) that compares augmented MBCT with follow-up sessions and that without follow-up sessions in preparation for a definitive RCT. METHODS: The study involves an 8-week MBCT with a 10-month follow-up. Patients aged 20 to 65 years who meet the Diagnostic and Statistical Manual of Mental Disorders, 4th edition (DSM-IV) criteria for panic disorder, agoraphobia, or social anxiety disorder, which is not remitted with usual treatment for at least 4 weeks, will be included in the study and randomly allocated to receive augmented MBCT with follow-up sessions or augmented MBCT without follow-up sessions. For this feasibility RCT, the primary outcomes are (1) study inclusion rate, (2) dropout rate, (3) attendance rate, and (4) mean and standard deviation of several clinical measures at 8 weeks and 5, 8, and 12 months. RESULTS: We started recruiting participants in January 2020, and 43 participants have been enrolled up to January 2021. The study is ongoing, and data collection will be completed by May 2022. CONCLUSIONS: This study is novel in terms of its design, which compares augmented MBCT with and without follow-up sessions. The limitations of the trial are as follows: (1) mixed participants in terms of the delivery mode of the intervention, and (2) lack of a pharmacotherapy-alone arm. Owing to its novelty and significance, this study will provide fruitful knowledge for future definitive RCTs. TRIAL REGISTRATION: UMIN Clinical Trials Registry UMIN000038626; https://tinyurl.com/2p9dtxzh. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): DERR1-10.2196/33776.