TFIIH-p52ΔC defines a ninth xeroderma pigmentosum complementation–group XP-J and restores TFIIH stability to p8-defective trichothiodystrophy
Yuka Nakazawa, Lin Ye, Yasuyoshi Oka, Hironobu Morinaga, Kana Kato, Mayuko Shimada, Kotaro Tsukada, Koyo Tsujikawa, Yosuke Nishio, Hiva Fassihi, Shehla Mohammed, Alan R. Lehmann, Tomoo Ogi
Yuka Nakazawa, Lin Ye, Yasuyoshi Oka, Hironobu Morinaga, Kana Kato, Mayuko Shimada, Kotaro Tsukada, Koyo Tsujikawa, Yosuke Nishio, Hiva Fassihi, Shehla Mohammed, Alan R. Lehmann, Tomoo Ogi
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Research Article Cell biology Dermatology Genetics

TFIIH-p52ΔC defines a ninth xeroderma pigmentosum complementation–group XP-J and restores TFIIH stability to p8-defective trichothiodystrophy

Abstract

Few drugs are available for rare diseases due to economic disincentives. However, tailored medications for extremely rare disorders (N-of-1) offer a ray of hope. Artificial antisense oligonucleotides (ASOs) are now best known for their use in spinal muscular atrophy (SMA). The success of nusinersen/Spinraza for SMA indicates the potential of ASO therapies for other rare conditions. We propose a strategy to develop N-of-1 ASOs for treating one form of trichothiodystrophy (TTD), a rare condition with multisystem abnormalities and reduced life expectancy, associated with instability and greatly reduced amounts of the DNA-repair/transcription factor TFIIH. The therapeutic targets carry mutations in GTF2H5, encoding the TFIIH-p8 subunit. This approach was inspired by the diagnosis and molecular dissection of a xeroderma pigmentosum (XP) case with mutations in GTF2H4, encoding the TFIIH-p52 subunit. This is newly classified as a ninth XP complementation–group, XP-J, identified 5 decades after the discovery of the other XP complementation–groups. The p8-p52 interaction is required to support the TFIIH-complex formation, and the patient’s p52 C-terminal truncation results in the complete absence of p8 in TFIIH. However, intriguingly, TFIIH remained stable in vivo, and the patient with XP-J did not exhibit any TTD-features. The aim of our ASO-design is to induce a C-terminal truncation of p52 and we have successfully stabilized TFIIH in p8-deficient cells from patients with TTD-A.

Authors

Yuka Nakazawa, Lin Ye, Yasuyoshi Oka, Hironobu Morinaga, Kana Kato, Mayuko Shimada, Kotaro Tsukada, Koyo Tsujikawa, Yosuke Nishio, Hiva Fassihi, Shehla Mohammed, Alan R. Lehmann, Tomoo Ogi

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Figure 4

Artificial antisense oligonucleotides (ASOs) designed to induce GTF2H4 alternative splicing facilitate p52 C-terminal truncation and promote TFIIH stability.

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Artificial antisense oligonucleotides (ASOs) designed to induce GTF2H4 a...
(A) Schematic representation of the GTF2H4 gene structure and the design of ASOs to induce intron 13 inclusion, leading to a frameshift and a C-terminal truncation of p52. In-frame stop codons in intron 13 (orange). (B) Induction of p52 C-terminal truncation in TTD-A cells treated with ASOs (24 hours). (C and D) Simultaneous blocking of the 5’ and 3’ splice sites of intron 13 facilitates efficient induction of the p52 truncation and TFIIH stabilization in TTD-A cells. In D, immunoprecipitation of XPB/p89 was performed. Asterisks indicate nonspecific products. (E) ASO treatment mostly rescues transcription in TTD cells. Transcription activity was measured by EU incorporation. Bars and error bars represent means and SEM, respectively, of experiments (n = 3, as indicated by the colored-circles and their corresponding plots). 20J/m2 UVC-irradiation. wo, without treatment; control, control-ASO treatment.