@article {351, title = {Biallelic mutations in the 3{\textquoteright} exonuclease TOE1 cause pontocerebellar hypoplasia and uncover a role in snRNA processing.}, journal = {Nat Genet}, volume = {49}, year = {2017}, month = {2017 Mar}, pages = {457-464}, abstract = {

Deadenylases are best known for degrading the poly(A) tail during mRNA decay. The deadenylase family has expanded throughout evolution and, in mammals, consists of 12 Mg-dependent 3{\textquoteright}-end RNases with substrate specificity that is mostly unknown. Pontocerebellar hypoplasia type 7 (PCH7) is a unique recessive syndrome characterized by neurodegeneration and ambiguous genitalia. We studied 12 human families with PCH7, uncovering biallelic, loss-of-function mutations in TOE1, which encodes an unconventional deadenylase. toe1-morphant zebrafish displayed midbrain and hindbrain degeneration, modeling PCH-like structural defects in vivo. Surprisingly, we found that TOE1 associated with small nuclear RNAs (snRNAs) incompletely processed spliceosomal. These pre-snRNAs contained 3{\textquoteright} genome-encoded tails often followed by post-transcriptionally added adenosines. Human cells with reduced levels of TOE1 accumulated 3{\textquoteright}-end-extended pre-snRNAs, and the immunoisolated TOE1 complex was sufficient for 3{\textquoteright}-end maturation of snRNAs. Our findings identify the cause of a neurodegenerative syndrome linked to snRNA maturation and uncover a key factor involved in the processing of snRNA 3{\textquoteright} ends.

}, keywords = {Alleles, Animals, Cerebellar Diseases, Exonucleases, Female, Humans, Male, Mice, Mutation, Neurodegenerative Diseases, Nuclear Proteins, RNA, Messenger, RNA, Small Nuclear, Spliceosomes, Zebrafish}, issn = {1546-1718}, doi = {10.1038/ng.3762}, author = {Lardelli, Rea M and Schaffer, Ashleigh E and Eggens, Veerle R C and Zaki, Maha S and Grainger, Stephanie and Sathe, Shashank and Van Nostrand, Eric L and Schlachetzki, Zinayida and Rosti, Basak and Akizu, Naiara and Scott, Eric and Silhavy, Jennifer L and Heckman, Laura Dean and Rosti, Rasim Ozgur and Dikoglu, Esra and Gregor, Anne and Guemez-Gamboa, Alicia and Musaev, Damir and Mande, Rohit and Widjaja, Ari and Shaw, Tim L and Markmiller, Sebastian and Marin-Valencia, Isaac and Davies, Justin H and de Meirleir, Linda and Kayserili, H{\"u}lya and Altunoglu, Umut and Freckmann, Mary Louise and Warwick, Linda and Chitayat, David and Blaser, Susan and {\c C}a{\u g}layan, Ahmet Okay and Bilguvar, Kaya and Per, H{\"u}seyin and Fagerberg, Christina and Christesen, Henrik T and Kibaek, Maria and Aldinger, Kimberly A and Manchester, David and Matsumoto, Naomichi and Muramatsu, Kazuhiro and Saitsu, Hirotomo and Shiina, Masaaki and Ogata, Kazuhiro and Foulds, Nicola and Dobyns, William B and Chi, Neil C and Traver, David and Spaccini, Luigina and Bova, Stefania Maria and Gabriel, Stacey B and G{\"u}nel, Murat and Valente, Enza Maria and Nassogne, Marie-Cecile and Bennett, Eric J and Yeo, Gene W and Baas, Frank and Lykke-Andersen, Jens and Gleeson, Joseph G} } @article {37, title = {Biallelic Mutations in Citron Kinase Link Mitotic Cytokinesis to Human Primary Microcephaly.}, journal = {Am J Hum Genet}, volume = {99}, year = {2016}, month = {2016 Aug 04}, pages = {501-10}, abstract = {

Cell division terminates with cytokinesis and cellular separation. Autosomal-recessive primary microcephaly (MCPH) is a neurodevelopmental disorder characterized by a reduction in brain and head size at birth in addition to non-progressive intellectual disability. MCPH is genetically heterogeneous, and 16 loci are known to be associated with loss-of-function mutations predominantly affecting centrosomal-associated proteins, but the multiple roles of centrosomes in cellular function has left questions about etiology. Here, we identified three families affected by homozygous missense mutations in CIT, encoding citron rho-interacting kinase (CIT), which has established roles in cytokinesis. All mutations caused substitution of conserved amino acid residues in the kinase domain and impaired kinase activity. Neural progenitors that were differentiated from induced pluripotent stem cells (iPSCs) derived from individuals with these mutations exhibited abnormal cytokinesis with delayed mitosis, multipolar spindles, and increased apoptosis, rescued by CRISPR/Cas9 genome editing. Our results highlight the importance of cytokinesis in the pathology of primary microcephaly.

}, keywords = {Alleles, Apoptosis, Centrosome, Child, Child, Preschool, Cytokinesis, Female, Genes, Recessive, Humans, Infant, Newborn, Intracellular Signaling Peptides and Proteins, Male, Microcephaly, Mitosis, Mutation, Missense, Pedigree, Protein Serine-Threonine Kinases}, issn = {1537-6605}, doi = {10.1016/j.ajhg.2016.07.004}, author = {Li, Hongda and Bielas, Stephanie L and Zaki, Maha S and Ismail, Samira and Farfara, Dorit and Um, Kyongmi and Rosti, Rasim O and Scott, Eric C and Tu, Shu and Chi, Neil C and Gabriel, Stacey and Erson-Omay, Emine Z and Ercan-Sencicek, A Gulhan and Yasuno, Katsuhito and {\c C}a{\u g}layan, Ahmet Okay and Kaymak{\c c}alan, Hande and Ekici, Bar{\i}{\c s} and Bilguvar, Kaya and G{\"u}nel, Murat and Gleeson, Joseph G} } @article {161, title = {Inactivating mutations in MFSD2A, required for omega-3 fatty acid transport in brain, cause a lethal microcephaly syndrome.}, journal = {Nat Genet}, volume = {47}, year = {2015}, month = {2015 Jul}, pages = {809-13}, abstract = {

Docosahexanoic acid (DHA) is the most abundant omega-3 fatty acid in brain, and, although it is considered essential, deficiency has not been linked to disease. Despite the large mass of DHA in phospholipids, the brain does not synthesize it. DHA is imported across the blood-brain barrier (BBB) through the major facilitator superfamily domain-containing 2a (MFSD2A) protein. MFSD2A transports DHA as well as other fatty acids in the form of lysophosphatidylcholine (LPC). We identify two families displaying MFSD2A mutations in conserved residues. Affected individuals exhibited a lethal microcephaly syndrome linked to inadequate uptake of LPC lipids. The MFSD2A mutations impaired transport activity in a cell-based assay. Moreover, when expressed in mfsd2aa-morphant zebrafish, mutants failed to rescue microcephaly, BBB breakdown and lethality. Our results establish a link between transport of DHA and LPCs by MFSD2A and human brain growth and function, presenting the first evidence of monogenic disease related to transport of DHA in humans.

}, keywords = {Adolescent, Animals, Biological Transport, Blood-Brain Barrier, Brain, Case-Control Studies, Child, Child, Preschool, Consanguinity, Fatty Acids, Omega-3, Female, Genes, Lethal, Genetic Association Studies, HEK293 Cells, Humans, Infant, Male, Mice, Knockout, Microcephaly, Mutation, Missense, Syndrome, Tumor Suppressor Proteins, Zebrafish}, issn = {1546-1718}, doi = {10.1038/ng.3311}, author = {Guemez-Gamboa, Alicia and Nguyen, Long N and Yang, Hongbo and Zaki, Maha S and Kara, Majdi and Ben-Omran, Tawfeg and Akizu, Naiara and Rosti, Rasim Ozgur and Rosti, Basak and Scott, Eric and Schroth, Jana and Copeland, Brett and Vaux, Keith K and Cazenave-Gassiot, Amaury and Quek, Debra Q Y and Wong, Bernice H and Tan, Bryan C and Wenk, Markus R and G{\"u}nel, Murat and Gabriel, Stacey and Chi, Neil C and Silver, David L and Gleeson, Joseph G} } @article {203, title = {Mutations in KATNB1 cause complex cerebral malformations by disrupting asymmetrically dividing neural progenitors.}, journal = {Neuron}, volume = {84}, year = {2014}, month = {2014 Dec 17}, pages = {1226-39}, abstract = {

Exome sequencing analysis of over 2,000 children with complex malformations of cortical development identified five independent (four homozygous and one compound heterozygous) deleterious mutations in KATNB1, encoding the regulatory subunit of the microtubule-severing enzyme Katanin. Mitotic spindle formation is defective in patient-derived fibroblasts, a consequence of disrupted interactions of mutant KATNB1 with KATNA1, the catalytic subunit of Katanin, and other microtubule-associated proteins. Loss of KATNB1 orthologs in zebrafish (katnb1) and flies (kat80) results in microcephaly, recapitulating the human phenotype. In the developing Drosophila optic lobe, kat80 loss specifically affects the asymmetrically dividing neuroblasts, which display supernumerary centrosomes and spindle abnormalities during mitosis, leading to cell cycle progression delays and reduced cell numbers. Furthermore, kat80 depletion results in dendritic arborization defects in sensory and motor neurons, affecting neural architecture. Taken together, we provide insight into the mechanisms by which KATNB1 mutations cause human cerebral cortical malformations, demonstrating its fundamental role during brain development.

}, keywords = {Adenosine Triphosphatases, Animals, Brain, Cell Count, Cell Division, Dendrites, Drosophila, Drosophila Proteins, Humans, Katanin, Mice, Microcephaly, Microtubule-Associated Proteins, Mutation, Neural Stem Cells, Neurogenesis, Optic Lobe, Nonmammalian, Spindle Apparatus, Zebrafish}, issn = {1097-4199}, doi = {10.1016/j.neuron.2014.12.014}, author = {Mishra-Gorur, Ketu and {\c C}a{\u g}layan, Ahmet Okay and Schaffer, Ashleigh E and Chabu, Chiswili and Henegariu, Octavian and Vonhoff, Fernando and Akg{\"u}m{\"u}{\c s}, G{\"o}zde Tu{\u g}ce and Nishimura, Sayoko and Han, Wenqi and Tu, Shu and Baran, Bur{\c c}in and G{\"u}m{\"u}{\c s}, Hakan and Dilber, Cengiz and Zaki, Maha S and Hossni, Heba A A and Rivi{\`e}re, Jean-Baptiste and Kayserili, H{\"u}lya and Spencer, Emily G and Rosti, Rasim O and Schroth, Jana and Per, H{\"u}seyin and Caglar, Caner and {\c C}a{\u g}lar, {\c C}a{\u g}ri and D{\"o}len, Duygu and Baranoski, Jacob F and Kumanda{\c s}, Sefer and Minja, Frank J and Erson-Omay, E Zeynep and Mane, Shrikant M and Lifton, Richard P and Xu, Tian and Keshishian, Haig and Dobyns, William B and Chi, Neil C and {\v S}estan, Nenad and Louvi, Angeliki and Bilguvar, Kaya and Yasuno, Katsuhito and Gleeson, Joseph G and G{\"u}nel, Murat} }