Tousled-like kinase 1 is a negative regulator of core transcription factors in murine embryonic stem cells

Abstract

Although the differentiation of pluripotent cells in embryonic stem cells (ESCs) is often associated with protein kinase-mediated signaling pathways and Tousled-like kinase 1 (Tlk1) is required for development in several species, the role of Tlk1 in ESC function remains unclear. Here, we used mouse ESCs to study the function of Tlk1 in pluripotent cells. The knockdown (KD)-based Tlk1-deficient cells showed that Tlk1 is not essential for ESC self-renewal in an undifferentiated state. However, Tlk1-KD cells formed irregularly shaped embryoid bodies and induced resistance to differentiation cues, indicating their failure to differentiate into an embryoid body. Consistent with their failure to differentiate, Tlk1-KD cells failed to downregulate the expression of undifferentiated cell markers including Oct4, Nanog, and Sox2 during differentiation, suggesting a negative role of Tlk1. Interestingly, Tlk1 overexpression sufficiently downregulated the expression of core pluripotency factors possibly irrespective of its kinase activity, thereby leading to a partial loss of self-renewal ability even in an undifferentiated state. Moreover, Tlk1 overexpression caused severe growth defects and G2/M phase arrest as well as apoptosis. Collectively, our data suggest that Tlk1 negatively regulates the expression of pluripotency factors, thereby contributing to the scheduled differentiation of mouse ESCs.

The Tousled-like kinases regulate genome and epigenome stability: implications in development and disease

“…H3.3 is required for H3K9me3 establishment in telomeres and endogenous retroviral elements (ERVs), as well as for H3K27me3 establishment at promoters of developmentally regulated genes [81][82][83]. Consistent with this, depletion of TLK1 delayed downregulation of pluripotency genes and impaired embryonic stem cell differentiation, suggesting impaired histone-mediated regulation of differentiation programs [108]. Numerous mutations in genes involved in epigenetic maintenance have been identified in ASD, including ATRX, that plays a prominent role in H3.3 deposition in heterochromatin at retrotransposons and telomeres [109,81], as well as KDM5B, KDM5C, SETD5, and DNMT3A [110].…”

Discretionary Transduction of MMP-Sensitized Tousled in Head and Neck Cancer

“…Breast cancer cells when co-cultured with fibroblasts depleted of TLK1 or TLK2 showed increased proliferation, 39 which suggested a pivotal role of TLKs in stromal signaling. Additionally, in murine embryonic stem cells, TLK1 downregulated expression of core pluripotency factors and promoted cell differentiation 40 . Therefore, it is possible that tumor control in response to TAT-TLK1B treatment is a result of its effects on surrounding fibroblasts and, or, cancer stem cells.…”

JIB-04, a Pan-Inhibitor of Histone Demethylases, Targets Histone-Lysine-Demethylase-Dependent AKT Pathway, Leading to Cell Cycle Arrest and Inhibition of Cancer Stem-Like Cell Properties in Hepatocellular Carcinoma Cells

“…Finally, to knockdown KDM4B, KDM4D, and KDM6B, HCC cells were infected with pLKO.1 viral particles with 6 µg/mL polybrene overnight. After 24 h, the infected cells were selected with 2.5 µg/mL puromycin [ 63 ].…”

“…qRT-PCR analysis was performed as described previously [ 63 ]. Total RNA was isolated using TRI-Reagent (Cat.…”