GemC1 governs multiciliogenesis through direct interaction with and transcriptional regulation of p73

Abstract

A distinct combination of transcription factors elicits the acquisition of a specific fate and the initiation of a differentiation program. Multiciliated cells (MCCs) are a specialized type of epithelial cells that possess dozens of motile cilia on their apical surface. Defects in cilia function have been associated with ciliopathies that affect many organs, including brain and airway epithelium. Here we show that the geminin coiled-coil domain-containing protein 1 GemC1 (also known as Lynkeas) regulates the transcriptional activation of p73, a transcription factor central to multiciliogenesis. Moreover, we show that GemC1 acts in a trimeric complex with transcription factor E2F5 and tumor protein p73 (officially known as TP73), and that this complex is important for the activation of the p73 promoter. We also provide in vivo evidence that GemC1 is necessary for p73 expression in different multiciliated epithelia. We further show that GemC1 regulates multiciliogenesis through the control of chromatin organization, and the epigenetic marks/tags of p73 and Foxj1. Our results highlight novel signaling cues involved in the commitment program of MCCs across species and tissues. This article has an associated First Person interview with the first author of the paper.

A Custom Ultra-Low-Cost 3D Bioprinter Supports Cell Growth and Differentiation

“…HeLa Kyoto and HEK293T cell lines were 2D cultured in Dulbecco's Modified Eagle Medium (DMEM, Gibco) supplemented with 10% fetal bovine serum (FBS, Gibco; Thermo Fisher Scientific, Inc.). Postnatal day 0 (P0) radial glial stem cells (pRGCs) were isolated from the mouse subventricular zone and 2D cultured in proliferation medium (PM) containing DMEM F12-Glutamax (Gibco; Thermo Fisher Scientific, Inc.), 10% (v/v) FBS, 1% (v/v) penicillin and streptomycin (P/S, Gibco; Thermo Fisher Scientific, Inc.), Epidermal Growth Factor (EGF, Peprotech) and Fibroblast Growth Factor (FGF, Peprotech) at a final concentration of 5µg/ml each, as previously described (Lalioti et al, 2019). Primary bone marrow-derived mesenchymal stem cells (MSCs) were isolated from the mouse femur, as described previously (Amend et al, 2016).…”

Fallopian Tube Basal Stem Cells Reproducing the Epithelial Sheets In Vitro—Stem Cell of Fallopian Epithelium

“…Previous studies reported that p73 was co-expressed with Foxj1 in basal cells of mice trachea, and was necessary for ependymal cell maturation, suggesting that p73 is needed for MCCs differentiation [ 28 , 36 ]. In p73 knockout mice, the FT showed defective ciliogenesis [ 28 , 30 , 37 ]. Thus, p73 and Ki67 have been shown to provide useful markers for identifying basal stem cells in FT.…”

GEMC1-MCIDAS transcriptional program regulates multiciliogenesis in the choroid plexus and acts as a barrier to tumorigenesis

“…As roof plate progenitors exit the cell cycle and commit to multiciliogenesis, TAp73 is turned on in multiciliated epithelial cells (Wildung et al 2019). Interestingly, both GEMC1 and MCIDAS were able to stimulate TAp73 expression (Lalioti et al 2019a). Gemc1 is expressed in differentiated epithelial cells, where its loss prevented activation of downstream targets including Mcidas , TAp73 and Foxj1 (Lalioti et al 2019a; Lewis and Stracker 2020).…”

“…GEMC1 and MCIDAS, complexed with cognate transcription partner E2Fs (E2F4 and E2F5), activate a network of downstream MCC factors including forkhead box J1 (FOXJ1), v-myb avian myeloblastosis viral oncogene homolog (MYB), and cyclin O (CCNO) (Tan et al 2013; Boon et al 2014; Ma et al 2014; Wallmeier et al 2014). Recent studies also showed that TAp73 , a P53 family member that acts downstream of Gemc1 in multiciliogenesis, plays an important role in the MCC program through activation of downstream genes including Foxj1 and Myb (Jackson and Attardi 2016; Marshall et al 2016; Nemajerova et al 2016; Lalioti et al 2019a). Disruption of the GEMC1-MCIDAS network leads to defective multiciliogenesis in different tissues, whereas mutations in both GMNC , the human ortholog of GEMC1 , and MCIDAS have been identified in human ciliopathies (Spassky and Meunier 2017; Lewis and Stracker 2020).…”