Transcription Elongation Factor Tcea3 Regulates the Pluripotent Differentiation Potential of Mouse Embryonic Stem Cells Via the Lefty1-Nodal-Smad2 Pathway

Abstract

Self-renewal and pluripotency are hallmark properties of pluripotent stem cells, including embryonic stem cells (ESCs) and iPS cells. Previous studies revealed the ESC-specific core transcription circuitry and showed that these core factors (e.g., Oct3/4, Sox2, and Nanog) regulate not only self-renewal but also pluripotent differentiation. However, it remains elusive how these two cell states are regulated and balanced during in vitro replication and differentiation. Here, we report that the transcription elongation factor Tcea3 is highly enriched in mouse ESCs and plays important roles in regulating the differentiation. Strikingly, altering Tcea3 expression in mouse ESCs did not affect self-renewal under non-differentiating condition; however, upon exposure to differentiating cues, its overexpression impaired in vitro differentiation capacity, and its knockdown biased differentiation towards mesodermal and endodermal fates. Furthermore, we identified Lefty1 as a downstream target of Tcea3 and show that the Tcea3-Lefty1-Nodal-Smad2 pathway is an innate program critically regulating cell fate choices between self-replication and differentiation commitment. Together, we propose that Tcea3 critically regulates pluripotent differentiation of mouse ESCs as a molecular rheostat of Nodal-Smad2/3 signaling.

Metabolic control of primed human pluripotent stem cell fate and function by the miR-200c–SIRT2 axis

“…6h). We next performed a fluorescence-based competition assay 35,36 . When wild-type H9 hESCs (WT) were mixed at a ratio of 1:1 with GFP-overexpressing H9 cells (GFP), the ratios of GFP + /total cells remained 50% up to five passages.…”

Transcriptional Regulation and Its Misregulation in Disease

“…In hematopoiesis, the TIF1γ transcription factor controls erythroid cell fate by interacting with P-TEFb and regulating transcription elongation at a specific set of target genes (Bai et al, 2010). Development generally appears to be dependent on proper elongation control; the transcription elongation factor Tcea3 (TFIIS) contributes to the ability of ESCs to respond appropriately to differentiation cues (Park et al, 2012) and mutations in the P-TEFb repressor HEXIM cause gross developmental defects (Nguyen et al, 2012). …”

Lefty1 and Lefty2 Control the Balance Between Self-Renewal and Pluripotent Differentiation of Mouse Embryonic Stem Cells

“…Secondary EB formation reflects the ability of mESCs to maintain their self-renewal capacity [17]. Previously, we reported that Lefty1-Nodal-pSmad2 signals regulated by Tcea3 form a critical pathway that regulates cell fate choices between self-renewal and commitment to differentiation [14]. As Lefty1 is a negative regulator of Nodal signaling and Smad2-mediated Activin/Nodal signaling is required for proper differentiation of mESCs toward the mesoendoderm lineages [16], we hypothesized that suppression of Lefty1 expression would facilitate differentiation of mESCs.…”

“…Recently, our research group reported that the Lefty1-Nodal-Smad2 pathway regulated by Tcea3 is an innate program to determine cell fate choices between self-replication and commitment to differentiation [14]. Here, we studied the function of Lefty isoforms in relation to pluripotency by examining the effect of Lefty1 or Lefty2 suppression on the selfrenewal and differentiation of mESCs.…”