Glutamate receptor RNA editing: a molecular analysis of GluR2, GluR5 and GluR6 in human brain tissues and in NT2 cells following in vitro neural differentiation.
The properties of some glutamate receptors are modified by RNA editing. This post-transcriptional mechanism involves the enzymatic deamination of specific adenosines in the pre-mRNA of the glutamate receptors, performed by specific RNA adenosine deaminases (ADARs). This event gives rise to the substitution of a gene-encoded amino acid with a different one that modifies the physiological properties of the ion channel. Here we report an analysis of the editing levels of AMPA GluR2, and kainate GluR5 and GluR6 in a human teratocarcinoma cell line (NT2) during in vitro neural differentiation, in conjunction with an analysis of the expression levels of GluR and ADAR genes. The editing levels were analysed using a specific standardised assay based on sequence analysis. This assay can be performed on all editing sites with a high level of sensitivity and reproducibility. Whereas GluR gene expression increased during NT2 neural differentiation, the expression of ADAR genes may be detected at comparable levels even in undifferentiated NT2 cells, remaining relatively stable during the differentiation process. Furthermore, most of the glutamate receptor editing sites increased their editing levels during NT2 neural differentiation, suggesting that the level of ADAR mRNAs is not closely related to the variable editing levels detected in the GluRs analysed. In human brain tissues, the editing levels appeared finely modulated in the different areas, indicating the possible formation of ion channels with different functional properties, thus generating a complex tissue-specific regulation of receptors and modulation of excitatory stimuli.
Barbon
Alessandro
A
Division of Biology and Genetics, Department of Biomedical Sciences and Biotechnologies, University of Brescia, Viale Europa 11, 25123 Brescia, Italy.
Vallini
Ivan
I
La Via
Luca
L
Marchina
Eleonora
E
Barlati
Sergio
S
D000243:Adenosine Deaminase / Q000235:genetics / Q000378:metabolism; D015152:Blotting, Northern; D001921:Brain / Q000033:anatomy & histology / Q000378:metabolism*; D002454:Cell Differentiation / Q000235:genetics*; D045744:Cell Line, Tumor; D006801:Humans; D066298:In Vitro Techniques; D008297:Male; D008967:Molecular Biology / Q000379:methods; D017393:RNA Editing; D012333:RNA, Messenger / Q000096:biosynthesis; D016601:RNA-Binding Proteins; D018091:Receptors, AMPA / Q000235:genetics / Q000378:metabolism; D017470:Receptors, Glutamate / Q000235:genetics / Q000378:metabolism*; D018092:Kainic Acid Receptors / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017422:Sequence Analysis, DNA; D018243:Teratocarcinoma; D013736:Testicular Neoplasms; D013997:Time Factors; D000097806:GluK2 Kainate Receptor
D000243:Adenosine Deaminase; D012333:RNA, Messenger; D016601:RNA-Binding Proteins; D018091:Receptors, AMPA; D017470:Receptors, Glutamate; D018092:Kainic Acid Receptors; D000097806:GluK2 Kainate Receptor; C567955:ADARB1 protein, human; C104722:glutamate receptor ionotropic, AMPA 2