Binding of p190RhoGEF to a destabilizing element on the light neurofilament mRNA is competed by BC1 RNA.
The enhancement of RNA-mediated motor neuron degeneration in transgenic mice by mutating a major mRNA instability determinant in a light neurofilament (NF-L) transgene implicates cognate RNA binding factors in the pathogenesis of motor neuron degeneration. p190RhoGEF is a neuron-enriched guanine exchange factor (GEF) that binds to the NF-L-destabilizing element, to c-Jun N-terminal kinase-interactive protein-1 (JIP-1), and to 14-3-3 and may link neurofilament expression to pathways affecting neuronal homeostasis. This study was undertaken to identify additional RNA species that bind p190RhoGEF and could affect interactions of the exchange factor with NF-L transcripts. The C-terminal domain of p190RhoGEF, containing the RNA-binding site, was expressed as a glutathione S-transferase fusion protein and was used as an affinity probe to isolate interactive RNAs in rat brain extracts. As expected, NF-L mRNA was identified as an RNA specie eluted from the affinity column. In addition, BC1 RNA was also found enriched in the bound RNA fraction. BC1 is a 152-nucleotide RNA that is highly expressed but untranslated in differentiated neurons. We show that BC1 and NF-L mRNA bind to a similar site in the C-terminal domain of p190RhoGEF, and their bindings to p190RhoGEF are readily cross-competed. Moreover, we identify a novel binding site in BC1 to account for its interaction with p190RhoGEF. The findings suggest a novel role of BC1 in differentiated neurons involving RNA-protein interactions of p190RhoGEF.
Ge
Weiwen
W
Division of Neuropathology, University of Pennsylvania Medical School, Philadelphia, Pennsylvania 19104-6100, USA.
Wu
Junhua
J
Zhai
Jinbin
J
Nie
Zhenying
Z
Lin
Hong
H
Schlaepfer
William W
WW
Canete-Soler
Rafaela
R
D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D001921:Brain / Q000502:physiology*; D004268:DNA-Binding Proteins; D020690:GTPase-Activating Proteins; D005982:Glutathione Transferase / Q000235:genetics; D020662:Guanine Nucleotide Exchange Factors / Q000378:metabolism*; D007382:Intermediate Filaments / Q000378:metabolism*; D051379:Mice; D008822:Mice, Transgenic; D008969:Molecular Sequence Data; D009410:Nerve Degeneration / Q000235:genetics; D016900:Neurofilament Proteins / Q000235:genetics*; D009474:Neurons / Q000502:physiology*; D009687:Nuclear Proteins / Q000378:metabolism*; D015347:RNA Probes; D012333:RNA, Messenger / Q000235:genetics* / Q000378:metabolism; D020733:RNA, Small Cytoplasmic / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D012097:Repressor Proteins; D014158:Transcription, Genetic
C513041:Arhgap35 protein, mouse; C513040:Arhgap35 protein, rat; C117734:BC1 RNA; D004268:DNA-Binding Proteins; D020690:GTPase-Activating Proteins; D020662:Guanine Nucleotide Exchange Factors; D016900:Neurofilament Proteins; D009687:Nuclear Proteins; D015347:RNA Probes; D012333:RNA, Messenger; D020733:RNA, Small Cytoplasmic; D011993:Recombinant Fusion Proteins; D012097:Repressor Proteins; C044882:neurofilament protein L; D005982:Glutathione Transferase