Nucleoporin TPR Affects C2C12 Myogenic Differentiation via Regulation of Myh4 Expression.

Jana Uhlířová,Jindřiška Fišerová,Tomáš Sieger,Lenka Šebestová,Karel Fišer,Pavel Hozák

doi:10.3390/cells10061271

Abstract

The nuclear pore complex (NPC) has emerged as a hub for the transcriptional regulation of a subset of genes, and this type of regulation plays an important role during differentiation. Nucleoporin TPR forms the nuclear basket of the NPC and is crucial for the enrichment of open chromatin around NPCs. TPR has been implicated in the regulation of transcription; however, the role of TPR in gene expression and cell differentiation has not been described. Here we show that depletion of TPR results in an aberrant morphology of murine proliferating C2C12 myoblasts (MBs) and differentiated C2C12 myotubes (MTs). The ChIP-Seq data revealed that TPR binds to genes linked to muscle formation and function, such as myosin heavy chain (Myh4), myocyte enhancer factor 2C (Mef2C) and a majority of olfactory receptor (Olfr) genes. We further show that TPR, possibly via lysine-specific demethylase 1 (LSD1), promotes the expression of Myh4 and Olfr376, but not Mef2C. This provides a novel insight into the mechanism of myogenesis; however, more evidence is needed to fully elucidate the mechanism by which TPR affects specific myogenic genes.

Highlights

Nucleoporins (NUPs) are proteins that form a nuclear pore complex (NPC) and enable specific transport between the cytoplasm and the nucleus
In MBs, Translocated promotor region (TPR) was located on the nucleoplasmic side of NPCs, as expected, but importantly within the nucleoplasm (Figure 1a–c and Figure S1b)
To decipher whether the deregulation of the differentiation of TPR-depleted cells is linked to altered expression of earlier differentiation markers, we examined the expression of Myf5 and MyoD1; we did not observe any difference between the control and TPR-depleted cells (Figure S3f–k)

Summary

Introduction

Nucleoporins (NUPs) are proteins that form a nuclear pore complex (NPC) and enable specific transport between the cytoplasm and the nucleus. NPCs [2,3,4,5], which are associated with open, transcriptionally active chromatin [6] This regulation is important during differentiation, a process characterized by vast changes in gene expression profiles [3,7,8,9]. TPR binds chromatin in vitro [16] and is crucial for the forming of heterochromatin exclusion zones in the vicinity of NPCs [6]. As these areas are important for transcriptional regulation, a question arises as to the role of TPR in this process and during differentiation

Methods

Results

Conclusion