RNA-binding protein PSPC1 promotes the differentiation-dependent nuclear export of adipocyte RNAs
Jiexin Wang, … , Douglas L. Black, Peter Tontonoz
Jiexin Wang, … , Douglas L. Black, Peter Tontonoz
Published February 13, 2017
Citation Information: J Clin Invest. 2017;127(3):987-1004. https://doi.org/10.1172/JCI89484.
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RNA-binding protein PSPC1 promotes the differentiation-dependent nuclear export of adipocyte RNAs

Abstract

A highly orchestrated gene expression program establishes the properties that define mature adipocytes, but the contribution of posttranscriptional factors to the adipocyte phenotype is poorly understood. Here we have shown that the RNA-binding protein PSPC1, a component of the paraspeckle complex, promotes adipogenesis in vitro and is important for mature adipocyte function in vivo. Cross-linking and immunoprecipitation followed by RNA sequencing revealed that PSPC1 binds to intronic and 3′-untranslated regions of a number of adipocyte RNAs, including the RNA encoding the transcriptional regulator EBF1. Purification of the paraspeckle complex from adipocytes further showed that PSPC1 associates with the RNA export factor DDX3X in a differentiation-dependent manner. Remarkably, PSPC1 relocates from the nucleus to the cytoplasm during differentiation, coinciding with enhanced export of adipogenic RNAs. Mice lacking PSPC1 in fat displayed reduced lipid storage and adipose tissue mass and were resistant to diet-induced obesity and insulin resistance due to a compensatory increase in energy expenditure. These findings highlight a role for PSPC1-dependent RNA maturation in the posttranscriptional control of adipose development and function.

Authors

Jiexin Wang, Prashant Rajbhandari, Andrey Damianov, Areum Han, Tamer Sallam, Hironori Waki, Claudio J. Villanueva, Stephen D. Lee, Ronni Nielsen, Susanne Mandrup, Karen Reue, Stephen G. Young, Julian Whitelegge, Enrique Saez, Douglas L. Black, Peter Tontonoz

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Figure 4

PSPC1 influences the expression of iCLIP-identified target RNAs.

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PSPC1 influences the expression of iCLIP-identified target RNAs. (A) Rea...
(A) Real-time PCR analysis of target gene mRNA expression in differentiated 10T1/2 cells stably expressing vector (Vect), N-terminal Flag-tagged PSPC1 (Fl-Pspc1), C-terminal Flag-tagged PSPC1 (Pspc1-Fl), untagged PSPC1 (Psp), or PSPC1 RNP mutant (RNP). Cells were stimulated to differentiate with DMI + 20 nM GW for 7 days. Comparison was made against vector control by 1-way ANOVA. Results represent 3 independent experiments. (B) Immunoblot analysis of target gene protein expression in differentiated 10T1/2 stable cell lines described in A. Results are representative of 3 independent experiments. (C) Real-time PCR analysis of target gene mRNA expression in undifferentiated 10T1/2 cells expressing vector (Vect), V5-tagged WT PSPC1 (Psp-V5), V5-tagged RRM1 deletion mutant (RRM1), or V5-tagged RRM2 deletion mutant (RRM2). Comparison was made against vector control by 1-way ANOVA. Results represent 3 independent experiments. (D) Immunoblot analysis of target gene protein expression in undifferentiated 10T1/2 cells described in C. Results are representative of 3 independent experiments. The immunoblots presented in D include replicate samples run on a parallel gel. (E) Real-time PCR analysis of target gene mRNA expression in undifferentiated 10T1/2 cells expressing PSPC1 shRNAs (shPspc1#1 and shPspc1#3) or lacZ shRNA control (shLacZ). Comparison was made against shlacZ control by 1-way ANOVA. Results represent 3 independent experiments. (F) Immunoblot analysis of target gene protein expression in undifferentiated 10T1/2 cells described in E. Results are representative of 3 independent experiments. Error bars represent mean + SEM. *P < 0.05, **P < 0.01.