NOVA-dependent regulation of cryptic NMD exons controls synaptic protein levels after seizure.
The neuronal RNA binding protein NOVA regulates splicing, shuttles to the cytoplasm, and co-localizes with target transcripts in dendrites, suggesting links between splicing and local translation. Here we identified >200 transcripts showing NOVA-dependent changes in abundance, but, surprisingly, HITS-CLIP revealed NOVA binds these RNAs in introns rather than 3' UTRs. This led us to discover NOVA-regulated splicing of cryptic exons within these introns. These exons triggered nonsense mediated decay (NMD), as UPF1 and protein synthesis were required for NOVA's effect on RNA levels. Their regulation was dynamic and physiologically relevant. The NMD exons were regulated by seizures, which also induced changes in Nova subcellular localization and mediated large changes in synaptic proteins, including proteins implicated in familial epilepsy. Moreover, Nova haploinsufficient mice had spontaneous epilepsy. The data reveal a hidden means of dynamic RNA regulation linking electrical activity to splicing and protein output, and of mediating homeostatic excitation/inhibition balance in neurons.DOI:http://dx.doi.org/10.7554/eLife.00178.001.
Laboratory of Molecular Neuro-Oncology ,  Rockefeller University ,  New York ,  United States.
Taesun
T
Eom
Chaolin
C
Zhang
Huidong
H
Wang
Kenneth
K
Lay
John
J
Fak
Jeffrey L
JL
Noebels
Robert B
RB
Darnell
D020413:3' Untranslated Regions; D000818:Animals; D000951:Antigens, Neoplasm / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D001921:Brain / Q000378:metabolism; D005091:Exons; D051379:Mice; D018345:Mice, Knockout; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism* / Q000502:physiology; D000090682:Neuro-Oncological Ventral Antigen; D012333:RNA, Messenger / Q000378:metabolism; D016601:RNA-Binding Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D012640:Seizures / Q000378:metabolism*; D013347:Subcellular Fractions; D013569:Synapses / Q000378:metabolism*
D020413:3' Untranslated Regions; D000951:Antigens, Neoplasm; D009419:Nerve Tissue Proteins; D000090682:Neuro-Oncological Ventral Antigen; D012333:RNA, Messenger; D016601:RNA-Binding Proteins
HITS-CLIP; Mouse; Nonsense mediated decay; RNA regulation; alternative splicing; epilepsy; neuronal biology