Biallelic mutations in nucleoporin NUP88 cause lethal fetal akinesia deformation sequence

• DOI: 10.1371/journal.pgen.1007845
• Publication Date: 2018-12-13T20:45:41Z
• Authors: Edith Bonnin; Pauline Cabochette; Alessandro Filosa; Ramona Jühlen; Shoko Komatsuzaki; Mohammed Hezwani; Achim Dickmanns; Valérie Martinelli; Marjorie Vermeersch; Lynn Supply; Nuno Martins; Laurence Pirenne; Gianina Ravenscroft; Marcus Lombard; Sarah Port; Christiane Spillner; Sandra Janssens; Ellen Roets; Jo Van Dorpe; Martin Lammens; Ralph H. Kehlenbach; Ralf Ficner; Nigel G. Laing; Katrin Hoffmann; Benoit Vanhollebeke; Birthe Fahrenkrog
• Keywords: Male; Models, Molecular; 0301 basic medicine; 572; Protein Conformation; CYTOPLASMIC FACE; Neuromuscular Junction; Muscle Proteins; Receptors, Nicotinic; QH426-470; Animals, Genetically Modified; Consanguinity; Mice; 03 medical and health sciences; Pregnancy; Medicine and Health Sciences; Genetics; Animals; Humans; Amino Acid Sequence; Zebrafish; Alleles; Arthrogryposis; COMPLEX; IDENTIFICATION; Sequence Homology, Amino Acid; ZEBRAFISH; NUCLEOCYTOPLASMIC TRANSPORT; Biology and Life Sciences; ASSOCIATION; Sciences bio-médicales et agricoles; Zebrafish Proteins; Pedigree; 3. Good health; Nuclear Pore Complex Proteins; Disease Models, Animal; Cardiovascular and Metabolic Diseases; Mutation; PROTEIN HOMOLOGY DETECTION; Female; Genes, Lethal; Human medicine; STRUCTURE PREDICTION; NUCLEAR-PORE; SUBCOMPLEX; Research Article

Nucleoporins build the nuclear pore complex (NPC), which, as sole gate for nuclear-cytoplasmic exchange, is of outmost importance for normal cell function. Defects in the process of nucleocytoplasmic transport or in its machinery have been frequently described in human diseases, such as cancer and neurodegenerative disorders, but only in a few cases of developmental disorders. Here we report biallelic mutations in the nucleoporin NUP88 as a novel cause of lethal fetal akinesia deformation sequence (FADS) in two families. FADS comprises a spectrum of clinically and genetically heterogeneous disorders with congenital malformations related to impaired fetal movement. We show that genetic disruption of nup88 in zebrafish results in pleiotropic developmental defects reminiscent of those seen in affected human fetuses, including locomotor defects as well as defects at neuromuscular junctions. Phenotypic alterations become visible at distinct developmental stages, both in affected human fetuses and in zebrafish, whereas early stages of development are apparently normal. The zebrafish phenotypes caused by nup88 deficiency are rescued by expressing wild-type Nup88 but not the disease-linked mutant forms of Nup88. Furthermore, using human and mouse cell lines as well as immunohistochemistry on fetal muscle tissue, we demonstrate that NUP88 depletion affects rapsyn, a key regulator of the muscle nicotinic acetylcholine receptor at the neuromuscular junction. Together, our studies provide the first characterization of NUP88 in vertebrate development, expand our understanding of the molecular events causing FADS, and suggest that variants in NUP88 should be investigated in cases of FADS.