Limits...
Cross-talking noncoding RNAs contribute to cell-specific neurodegeneration in SCA7.

Tan JY, Vance KW, Varela MA, Sirey T, Watson LM, Curtis HJ, Marinello M, Alves S, Steinkraus BR, Cooper S, Nesterova T, Brockdorff N, Fulga TA, Brice A, Sittler A, Oliver PL, Wood MJ, Ponting CP, Marques AC - Nat. Struct. Mol. Biol. (2014)

Bottom Line: What causes the tissue-specific pathology of diseases resulting from mutations in housekeeping genes?We found that STAGA is required for the transcription initiation of miR-124, which in turn mediates the post-transcriptional cross-talk between lnc-SCA7, a conserved long noncoding RNA, and ATXN7 mRNA.Our results illustrate how noncoding RNA-mediated feedback regulation of a ubiquitously expressed housekeeping gene may contribute to specific neurodegeneration.

View Article: PubMed Central - PubMed

Affiliation: 1] Medical Research Council Functional Genomics Unit, University of Oxford, Oxford, UK. [2] Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK.

ABSTRACT
What causes the tissue-specific pathology of diseases resulting from mutations in housekeeping genes? Specifically, in spinocerebellar ataxia type 7 (SCA7), a neurodegenerative disorder caused by a CAG-repeat expansion in ATXN7 (which encodes an essential component of the mammalian transcription coactivation complex, STAGA), the factors underlying the characteristic progressive cerebellar and retinal degeneration in patients were unknown. We found that STAGA is required for the transcription initiation of miR-124, which in turn mediates the post-transcriptional cross-talk between lnc-SCA7, a conserved long noncoding RNA, and ATXN7 mRNA. In SCA7, mutations in ATXN7 disrupt these regulatory interactions and result in a neuron-specific increase in ATXN7 expression. Strikingly, in mice this increase is most prominent in the SCA7 disease-relevant tissues, namely the retina and cerebellum. Our results illustrate how noncoding RNA-mediated feedback regulation of a ubiquitously expressed housekeeping gene may contribute to specific neurodegeneration.

Show MeSH

Related in: MedlinePlus

Contribution of noncoding RNAs to the tissue-specific pathology of SCA7(A) Fold difference in expression of mature miR-124 abundance (dark grey), lnc-SCA7 (blue) and ATXN7 (red) in SCA7 patient fibroblasts with 42, 49, or 55 expanded ATXN7 polyQ repeats relative to healthy control (white). (B) ChIP-qPCR revealed significantly decreased enrichment, relative to IgG control, in GCN5 binding at miR-124 promoters in SCA7100Q/100Q mice (dark grey) relative to control animals (white). (C) Correlation between the fold difference in expression levels between lnc-SCA7 (Y-axis, blue) and Atxn7 (y-axis, red) with miR-124 (x-axis) in SCA7266Q/5Q mice as measured using qRT-PCR and relative to matched controls, SCA75Q/5Q. (D and E) RNA in-situ hybridization of miR-124 and Atxn7 in the retina and cerebellum of SCA7266Q/5Q mice and littermate SCA75Q/5Q controls in the retina (D; ganglion cell layer (GCL), inner nuclear layer (INL), outer nuclear layer (ONL)) and cerebellum (E; granule cell layer (GCL), Purkinje cell layer (PCL)). Error bars s.d.m. for 3 cell cultures per condition (A) and cerebellum tissues derived from 3 individual mice per condition (B). ** p < 0.01; *** p < 0.001; NS p>0.05; Two-tailed Student’s t-test n = 3 biological replicates per condition). Error bars represent s.d.m. **, p < 0.01; ***, p < 0.001; Student’s t-test.
© Copyright Policy
Related In: Results  -  Collection


getmorefigures.php?uid=PMC4255225&req=5

Figure 5: Contribution of noncoding RNAs to the tissue-specific pathology of SCA7(A) Fold difference in expression of mature miR-124 abundance (dark grey), lnc-SCA7 (blue) and ATXN7 (red) in SCA7 patient fibroblasts with 42, 49, or 55 expanded ATXN7 polyQ repeats relative to healthy control (white). (B) ChIP-qPCR revealed significantly decreased enrichment, relative to IgG control, in GCN5 binding at miR-124 promoters in SCA7100Q/100Q mice (dark grey) relative to control animals (white). (C) Correlation between the fold difference in expression levels between lnc-SCA7 (Y-axis, blue) and Atxn7 (y-axis, red) with miR-124 (x-axis) in SCA7266Q/5Q mice as measured using qRT-PCR and relative to matched controls, SCA75Q/5Q. (D and E) RNA in-situ hybridization of miR-124 and Atxn7 in the retina and cerebellum of SCA7266Q/5Q mice and littermate SCA75Q/5Q controls in the retina (D; ganglion cell layer (GCL), inner nuclear layer (INL), outer nuclear layer (ONL)) and cerebellum (E; granule cell layer (GCL), Purkinje cell layer (PCL)). Error bars s.d.m. for 3 cell cultures per condition (A) and cerebellum tissues derived from 3 individual mice per condition (B). ** p < 0.01; *** p < 0.001; NS p>0.05; Two-tailed Student’s t-test n = 3 biological replicates per condition). Error bars represent s.d.m. **, p < 0.01; ***, p < 0.001; Student’s t-test.

Mentions: We first validated these predictions in a human model of SCA7 by comparing the levels of ATXN7, lnc-SCA7 and miR-124 in fibroblasts derived from three SCA7 patients, who carry 42, 49 or 55 polyQ ATXN7 repeat expansions, against their levels in control fibroblasts (10 polyQ-repeats). Expression levels of miR-124 were reduced by more than two-fold (45% of control), whereas transcript abundances of lnc-SCA7 and ATXN7 were increased substantially (by up to 1.8-fold and 5.2-fold, respectively) in these patients’ cells (Figure 5A). Furthermore, decreased levels of endogenous miR-124 (62% of control) in human fibroblasts were associated with an increase abundance of both lnc-SCA7 and ATXN7 (1.22- and 1.27-fold respectively, Supplementary Figure 6), which supports the direct contribution of this miRNA to the post-transcriptional modulation of these two transcripts’ levels in fibroblasts.


Cross-talking noncoding RNAs contribute to cell-specific neurodegeneration in SCA7.

Tan JY, Vance KW, Varela MA, Sirey T, Watson LM, Curtis HJ, Marinello M, Alves S, Steinkraus BR, Cooper S, Nesterova T, Brockdorff N, Fulga TA, Brice A, Sittler A, Oliver PL, Wood MJ, Ponting CP, Marques AC - Nat. Struct. Mol. Biol. (2014)

Contribution of noncoding RNAs to the tissue-specific pathology of SCA7(A) Fold difference in expression of mature miR-124 abundance (dark grey), lnc-SCA7 (blue) and ATXN7 (red) in SCA7 patient fibroblasts with 42, 49, or 55 expanded ATXN7 polyQ repeats relative to healthy control (white). (B) ChIP-qPCR revealed significantly decreased enrichment, relative to IgG control, in GCN5 binding at miR-124 promoters in SCA7100Q/100Q mice (dark grey) relative to control animals (white). (C) Correlation between the fold difference in expression levels between lnc-SCA7 (Y-axis, blue) and Atxn7 (y-axis, red) with miR-124 (x-axis) in SCA7266Q/5Q mice as measured using qRT-PCR and relative to matched controls, SCA75Q/5Q. (D and E) RNA in-situ hybridization of miR-124 and Atxn7 in the retina and cerebellum of SCA7266Q/5Q mice and littermate SCA75Q/5Q controls in the retina (D; ganglion cell layer (GCL), inner nuclear layer (INL), outer nuclear layer (ONL)) and cerebellum (E; granule cell layer (GCL), Purkinje cell layer (PCL)). Error bars s.d.m. for 3 cell cultures per condition (A) and cerebellum tissues derived from 3 individual mice per condition (B). ** p < 0.01; *** p < 0.001; NS p>0.05; Two-tailed Student’s t-test n = 3 biological replicates per condition). Error bars represent s.d.m. **, p < 0.01; ***, p < 0.001; Student’s t-test.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4255225&req=5

Figure 5: Contribution of noncoding RNAs to the tissue-specific pathology of SCA7(A) Fold difference in expression of mature miR-124 abundance (dark grey), lnc-SCA7 (blue) and ATXN7 (red) in SCA7 patient fibroblasts with 42, 49, or 55 expanded ATXN7 polyQ repeats relative to healthy control (white). (B) ChIP-qPCR revealed significantly decreased enrichment, relative to IgG control, in GCN5 binding at miR-124 promoters in SCA7100Q/100Q mice (dark grey) relative to control animals (white). (C) Correlation between the fold difference in expression levels between lnc-SCA7 (Y-axis, blue) and Atxn7 (y-axis, red) with miR-124 (x-axis) in SCA7266Q/5Q mice as measured using qRT-PCR and relative to matched controls, SCA75Q/5Q. (D and E) RNA in-situ hybridization of miR-124 and Atxn7 in the retina and cerebellum of SCA7266Q/5Q mice and littermate SCA75Q/5Q controls in the retina (D; ganglion cell layer (GCL), inner nuclear layer (INL), outer nuclear layer (ONL)) and cerebellum (E; granule cell layer (GCL), Purkinje cell layer (PCL)). Error bars s.d.m. for 3 cell cultures per condition (A) and cerebellum tissues derived from 3 individual mice per condition (B). ** p < 0.01; *** p < 0.001; NS p>0.05; Two-tailed Student’s t-test n = 3 biological replicates per condition). Error bars represent s.d.m. **, p < 0.01; ***, p < 0.001; Student’s t-test.
Mentions: We first validated these predictions in a human model of SCA7 by comparing the levels of ATXN7, lnc-SCA7 and miR-124 in fibroblasts derived from three SCA7 patients, who carry 42, 49 or 55 polyQ ATXN7 repeat expansions, against their levels in control fibroblasts (10 polyQ-repeats). Expression levels of miR-124 were reduced by more than two-fold (45% of control), whereas transcript abundances of lnc-SCA7 and ATXN7 were increased substantially (by up to 1.8-fold and 5.2-fold, respectively) in these patients’ cells (Figure 5A). Furthermore, decreased levels of endogenous miR-124 (62% of control) in human fibroblasts were associated with an increase abundance of both lnc-SCA7 and ATXN7 (1.22- and 1.27-fold respectively, Supplementary Figure 6), which supports the direct contribution of this miRNA to the post-transcriptional modulation of these two transcripts’ levels in fibroblasts.

Bottom Line: What causes the tissue-specific pathology of diseases resulting from mutations in housekeeping genes?We found that STAGA is required for the transcription initiation of miR-124, which in turn mediates the post-transcriptional cross-talk between lnc-SCA7, a conserved long noncoding RNA, and ATXN7 mRNA.Our results illustrate how noncoding RNA-mediated feedback regulation of a ubiquitously expressed housekeeping gene may contribute to specific neurodegeneration.

View Article: PubMed Central - PubMed

Affiliation: 1] Medical Research Council Functional Genomics Unit, University of Oxford, Oxford, UK. [2] Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK.

ABSTRACT
What causes the tissue-specific pathology of diseases resulting from mutations in housekeeping genes? Specifically, in spinocerebellar ataxia type 7 (SCA7), a neurodegenerative disorder caused by a CAG-repeat expansion in ATXN7 (which encodes an essential component of the mammalian transcription coactivation complex, STAGA), the factors underlying the characteristic progressive cerebellar and retinal degeneration in patients were unknown. We found that STAGA is required for the transcription initiation of miR-124, which in turn mediates the post-transcriptional cross-talk between lnc-SCA7, a conserved long noncoding RNA, and ATXN7 mRNA. In SCA7, mutations in ATXN7 disrupt these regulatory interactions and result in a neuron-specific increase in ATXN7 expression. Strikingly, in mice this increase is most prominent in the SCA7 disease-relevant tissues, namely the retina and cerebellum. Our results illustrate how noncoding RNA-mediated feedback regulation of a ubiquitously expressed housekeeping gene may contribute to specific neurodegeneration.

Show MeSH
Related in: MedlinePlus