Post-transcriptional regulation of neuro-oncological ventral antigen 1 by the neuronal RNA-binding proteins ELAV.
Alternative splicing of pre-mRNAs plays an important role in generating biological and functional diversity. Neuro-oncological ventral antigen 1 (Nova1) is a neuron-specific splicing factor that controls the alternative processing of a wide array of mRNAs important for synaptic activity. It is essential for the proper development of the mammalian motor system and for the survival of motoneurons. Because Nova1 gene contains putative regulatory AU-rich elements (ARE) in its highly conserved 3'-untranslated region, we investigated whether its expression is regulated by post-transcriptional mechanisms mediated by ARE-binding proteins. Among these, the neuronal ELAV (nELAV) factors are interesting candidates, because their RNA binding activity is necessary for neuronal differentiation and maintenance. By analysis of ribonucleoprotein complexes in vivo and in vitro we demonstrated that the Nova1 mRNA is a novel target of the nELAV proteins. We defined the nELAV binding site by functional experiments with luciferase reporter gene and Nova1 3'-untranslated region deletion sequences. Gene silencing and overexpression of the nELAV member HuD in motoneuronal NSC34 cells indicate that Nova1 mRNA stability and translation are positively and strongly controlled by the nELAV proteins. In addition, nELAV phosphorylation by a PKC-dependent pathway induces the recruitment of Nova1 mRNA to polysomes. Noteworthy, we found that nELAV proteins are also able to modulate Nova1 splicing activity on its target genes. Our data indicate nELAV proteins as the first factors affecting the expression and activity of the neuronal splicing regulator Nova1 and, consequently, as major candidates for the physiological modulation of Nova1-dependent processing of pre-mRNAs in neurons.
Ratti
Antonia
A
Department of Neurological Sciences, Dino Ferrari Centre, University of Milan Medical School, IRCCS Istituto Auxologico Italiano, 20095 Cusano, Milan, Italy. antonia.ratti@unimi.it
Fallini
Claudia
C
Colombrita
Claudia
C
Pascale
Alessia
A
Laforenza
Umberto
U
Quattrone
Alessandro
A
Silani
Vincenzo
V
D020413:3' Untranslated Regions / Q000235:genetics / Q000378:metabolism*; D017398:Alternative Splicing / Q000502:physiology; D000818:Animals; D000951:Antigens, Neoplasm / Q000096:biosynthesis* / Q000235:genetics; D002454:Cell Differentiation / Q000502:physiology*; D051959:ELAV Proteins / Q000235:genetics / Q000378:metabolism*; D000067779:ELAV-Like Protein 4; D006801:Humans; D051379:Mice; D046912:Multiprotein Complexes / Q000235:genetics / Q000378:metabolism; D009419:Nerve Tissue Proteins / Q000096:biosynthesis* / Q000235:genetics; D000090682:Neuro-Oncological Ventral Antigen; D009474:Neurons / Q000166:cytology / Q000378:metabolism*; D014176:Protein Biosynthesis / Q000502:physiology*; D020871:RNA Stability / Q000502:physiology*; D016601:RNA-Binding Proteins / Q000096:biosynthesis* / Q000235:genetics
D020413:3' Untranslated Regions; D000951:Antigens, Neoplasm; D051959:ELAV Proteins; D000067779:ELAV-Like Protein 4; C498010:ELAVL4 protein, human; C498011:Elavl4 protein, mouse; D046912:Multiprotein Complexes; D009419:Nerve Tissue Proteins; D000090682:Neuro-Oncological Ventral Antigen; D016601:RNA-Binding Proteins