Human Molecular Genetics, 2016, Vol. 25, No. 2
291–307
doi: 10.1093/hmg/ddv471
Advance Access Publication Date: 24 November 2015
Original Article
ORIGINAL ARTICLE
Deficiency of the zinc finger protein ZFP106 causes
motor and sensory neurodegeneration
1
MRC Mammalian Genetics Unit, Harwell, Oxfordshire OX11 0RD, UK, 2UCL Institute of Neurology and MRC Centre
for Neuromuscular Disease, Queen Square, London WC1N 3BG, UK, 3Health Sciences, University of Aberdeen,
Aberdeen AB25 2ZD, UK, 4Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford OX3 9DU,
UK, 5Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridgeshire CB10 1SA, UK and
6
UCL Genetics Institute, London WC1E 6BT, UK
*To whom correspondence should be addressed. Email: (A.A.)/e.fi
[email protected] (E.M.C.F.)/ (L.G.)
Abstract
Zinc finger motifs are distributed amongst many eukaryotic protein families, directing nucleic acid–protein and protein–protein
interactions. Zinc finger protein 106 (ZFP106) has previously been associated with roles in immune response, muscle
differentiation, testes development and DNA damage, although little is known about its specific function. To further investigate
the function of ZFP106, we performed an in-depth characterization of Zfp106 deficient mice (Zfp106−/−), and we report a novel
role for ZFP106 in motor and sensory neuronal maintenance and survival. Zfp106−/− mice develop severe motor abnormalities,
major deficits in muscle strength and histopathological changes in muscle. Intriguingly, despite being highly expressed
throughout the central nervous system, Zfp106−/− mice undergo selective motor and sensory neuronal and axonal degeneration
specific to the spinal cord and peripheral nervous system. Neurodegeneration does not occur during development of Zfp106−/−
mice, suggesting that ZFP106 is likely required for the maintenance of mature peripheral motor and sensory neurons. Analysis
of embryonic Zfp106−/− motor neurons revealed deficits in mitochondrial function, with an inhibition of Complex I within
the mitochondrial electron transport chain. Our results highlight a vital role for ZFP106 in sensory and motor neuron
maintenance and reveal a novel player in mitochondrial dysfunction and neurodegeneration.
†
Equal contributors in alphabetical order.
Received: October 15, 2015. Revised: November 9, 2015. Accepted: November 11, 2015
© The Author 2015. Published by Oxford University Press.
This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/),
which permits unrestricted reuse, distribution, and reproduction in any medium, provided the original work is properly cited.
291
Peter I. Joyce1, Pietro Fratta2,†, Allison S. Landman1,†, Philip Mcgoldrick2,†,
Henning Wackerhage3, Michael Groves2, Bharani Shiva Busam3, Jorge Galino4,
Silvia Corrochano1, Olga A. Beskina2, Christopher Esapa1, Edward Ryder4,
Sarah Carter1, Michelle Stewart1, Gemma Codner1, Helen Hilton1,
Lydia Teboul1, Jennifer Tucker1, Arimantas Lionikas3, Jeanne Estabel5,
Ramiro Ramirez-Solis5, Jacqueline K. White5, Sebastian Brandner2,
Vincent Plagnol6, David L. H. Bennet4, Andrey Y. Abramov2, Linda Greensmith2,*,
Elizabeth M. C. Fisher2,* and Abraham Acevedo-Arozena1,*
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| Human Molecular Genetics, 2016, Vol. 25, No. 2
Introduction
Results
Zfp106 deficiency causes progressive motor
abnormalities
A knockout first promoter-less allele (tm1a(KOMP)Wtsi) within
Zfp106 was created by The Sanger Mouse Genetics Project (http://
www.sanger.ac.uk/mouseportal/) through KOMP (9). The construct targets Zfp106 intron 1 on chromosome 2 and includes a
β-galactosidase (LacZ) reporter allele (see ‘Materials and Methods’). Mice homozygous for the tm1a(KOMP)Wtsi allele in
Zfp106 (Zfp106−/−) are born in Mendelian ratios (data not shown)
and both Zfp106 −/−male and female mice develop an abnormal
gait from ∼3 weeks of age, which deteriorates with age, causing
animals to inaccurately place their limbs, especially their hindlimbs, when walking across a wire grate (Supplementary Material, Movie S1). Zfp106−/− animals also become severely kyphotic
and develop limb grasping defects at 15-weeks of age whereby
they pull all of their limbs into their body (Fig. 1A and Supplementary Material, Movie S1).
ZFP106 is a zinc finger protein with proposed roles in transcriptional control, RNA metabolism, the immune response, muscle
development and differentiation and testes development (1–3).
Phosphorylation of ZFP106 increases following DNA damage,
which might suggest a possible role in the DNA damage response
pathway (4). Recently, ZFP106 has been identified as a novel factor regulating transcription initiation by targeting RNA-polymerase I to the promoter of ribosomal RNA genes (5), linking for the
first time ZFP106 function and RNA metabolism. Interestingly,
the human gene encoding ZFP106 (ZFN106) is located within a
familial amyotrophic lateral sclerosis (ALS) locus (ALS5) on
human chromosome 15, while human ZFP106 is proposed to localize to the nucleolus (1).
Zfp106 encodes a 1888-amino acid protein with two N-terminal
C2H2 zinc finger motifs, two C-terminal CWCH2 zinc finger motifs
and seven WD40 repeats (2,3,6). Zinc finger motifs are important
for protein–protein interactions and nucleic-acid binding (7),
whilst WD40 repeats are involved in protein–protein interaction
and facilitate the formation of large multi-protein complexes (8).
Putative orthologues of Zfp106 are only found in mammals and exhibit a high degree of conservation between species.
Zfp106 mRNA expression is proposed to be driven from two
promoters, with the resulting transcripts producing a number
of isoforms (2). Full-length ZFP106 (ZNF106) mRNA is expressed
ubiquitously and expression is particularly high in the heart,
skeletal muscle and testis (2). Nuclear respiratory factor-1 (NRF-1)
can activate Zfp106 mRNA expression, with expression patterns
of full-length Zfp106 and Nrf1 mRNA coinciding in mouse embryos (2). A short isoform is specifically expressed in skeletal
muscle, regulated by myogenin, and is strongly upregulated during myogenic differentiation (2).
While previous research on ZFP106 indicates different functions, in this study we have created the first ZFP106 animal
model to further understand its in vivo functions. We have
taken advantage of the resource provided by the international
Knock Out Mouse Project (KOMP) (9) and the Sanger Mouse Genetics Project to further elucidate Zfp106 function. Mice homozygous for the knockout first promoter-less allele (tm1a(KOMP)
Wtsi) in Zfp106 develop severe gait and motor abnormalities
that deteriorate with age. The motor abnormalities exhibited by
Zfp106−/− mice are likely due to a severe progressive adult-onset
degenerative sensory-motor axonopathy.
To assess Zfp106 expression we performed whole-genome
transcriptomic analysis (RNA-seq) on spinal cord and qPCR on
spinal cord and brain from adult wild-type (...truncated)
