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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Research Article Metabolism

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 6

PSPC1 facilitates nucleocytoplasmic export of target mRNAs.

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PSPC1 facilitates nucleocytoplasmic export of target mRNAs. (A) Real-tim...
(A) Real-time PCR analysis of PSPC1 target transcripts at multiple time points following actinomycin D treatment in differentiated 10T1/2 cells stably expressing vector (Vect), Flag-tagged PSPC1 (Fl-Pspc1), or untagged PSPC1 (Psp). Results represent 3 independent experiments. (B) Real-time PCR analysis of PSPC1 target transcripts at multiple time points following actinomycin D treatment in differentiated 10T1/2 cells stably expressing PSPC1 shRNA (shPspc1) or lacZ shRNA (shLacZ). Results represent 2 independent experiments. (C) Real-time PCR analysis of PSPC1 target transcripts in the nuclear and cytoplasmic fractions of 10T1/2 cells expressing vector (Vect), Fl-Pspc1, or Psp. Values represent the cytoplasmic-to-nuclear ratio of each transcript. Lxrb served as a negative control. Comparison was made against vector control by 1-way ANOVA. Results represent 3 independent experiments. (D) Real-time PCR analysis of gene expression in control or PSPC1-transduced 10T1/2 cells transfected with nontargeting siRNA control (siNC) or siRNA directed against Ddx3x (siDdx3x). Comparison was made against siNC control by Student’s t test. Results represent 2 independent experiments. (E) Immunoblot analysis of protein extracts from control or PSPC1-transduced 10T1/2 cells transfected with nontargeting siRNA control (siNC) or siRNA directed against Ddx3x (siDdx3x). Results are representative of 2 independent experiments. Error bars represent mean + SEM. *P < 0.05, **P < 0.01.