Related Experiment Video For SCA12
Updated: Jul 16, 2025

Cerebellar Regional Dissection for Molecular Analysis
Published on: December 5, 2020
Bidirectional Transcription at the PPP2R2B Gene Locus in Spinocerebellar Ataxia Type 12
Chengqian Zhou1, Hans B Liu1, Fatemeh Jahanbakhsh2
1Department of Psychiatry and Behavioral Sciences, Division of Neurobiology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.
Background:
Spinocerebellar ataxia type 12 (SCA12) is a neurodegenerative disease caused by expansion of a CAG repeat in the PPP2R2B gene.
Objective:
In this study, we tested the hypothesis that the PPP2R2B antisense (PPP2R2B-AS1) transcript containing a CUG repeat is expressed and contributes to SCA12 pathogenesis.
Methods:
Expression of PPP2R2B-AS1 transcript was detected in SCA12 human induced pluripotent stem cells (iPSCs), iPSC-derived NGN2 neurons, and SCA12 knock-in mouse brains using strand-specific reverse transcription polymerase chain reaction. The tendency of expanded PPP2R2B-AS1 (expPPP2R2B-AS1) RNA to form foci, a marker of toxic processes involving mutant RNAs, was examined in SCA12 cell models by fluorescence in situ hybridization. The apoptotic effect of expPPP2R2B-AS1 transcripts on SK-N-MC neuroblastoma cells was evaluated by caspase 3/7 activity. Western blot was used to examine the expression of repeat associated non-ATG-initiated translation of expPPP2R2B-AS1 transcript in SK-N-MC cells.
Results:
The repeat region in the PPP2R2B gene locus is bidirectionally transcribed in SCA12 iPSCs, iPSC-derived NGN2 neurons, and SCA12 mouse brains. Transfected expPPP2R2B-AS1 transcripts induce apoptosis in SK-N-MC cells, and the apoptotic effect may be mediated, at least in part, by the RNA secondary structure. The expPPP2R2B-AS1 transcripts form CUG RNA foci in SK-N-MC cells. expPPP2R2B-AS1 transcript is translated in the alanine open reading frame (ORF) via repeat-associated non-ATG translation, which is diminished by single-nucleotide interruptions within the CUG repeat and MBNL1 overexpression.
Conclusions:
These findings suggest that PPP2R2B-AS1 contributes to SCA12 pathogenesis and may therefore provide a novel therapeutic target for the disease. © 2023 International Parkinson and Movement Disorder Society.
Related Concept Videos
piRNA - Piwi-interacting RNAs
The Spindle Assembly Checkpoint
Many proteins function together to control the spindle assembly checkpoint. Mutations affecting these proteins may allow cells to proceed into anaphase prematurely, resulting in the...
Alternative RNA Splicing
There are five types of alternative RNA splicing that vary in the ways the pre-mRNA segments are removed or retained in the mature mRNA. The first...
RNA Splicing
Translation
Translation Produces the Building Blocks of Life
Proteins are...
Pleiotropy

