Masek, M. | Search bioRxiv

bioRxiv2021

Mass Cytometric and Transcriptomic Profiling of Epithelial-Mesenchymal Transitions in Human Mammary Cell Lines

Epithelial-mesenchymal transition (EMT) equips breast cancer cells for metastasis and treatment resistance. Inhibition and elimination of EMT-undergoing cells are therefore promising therapy approaches. However, detecting EMT-undergoing cells is challenging due to the intrinsic heterogeneity of cancer cells and the phenotypic diversity of EMT programs. Here, we profiled EMT transition phenotypes in four non-cancerous human mammary epithelial cell lines using a FACS surface marker screen, RNA sequencing, and mass cytometry. EMT was induced in the HMLE and MCF10A cell lines and in the HMLE-Twist-ER and HMLE-Snail-ER cell lines by chronic exposure to TGF{beta}1 or 4-hydroxytamoxifen, respectively. We observed a spectrum of EMT transition phenotypes in each cell line and the spectrum varied across the time course. Our data provide multiparametric insights at single-cell level into the phenotypic diversity of EMT at different time points and in four human cellular models. These insights are valuable to better understand the complexity of EMT, to compare EMT transitions between the cellular models used herein, and for the design of EMT time course experiments. O_TBL View this table: org.highwire.dtl.DTLVardef@10d2b87org.highwire.dtl.DTLVardef@1a4cc67org.highwire.dtl.DTLVardef@67bc95org.highwire.dtl.DTLVardef@8df40dorg.highwire.dtl.DTLVardef@1919e7c_HPS_FORMAT_FIGEXP M_TBL C_TBL Mendeley Data: DOI: 10.17632/pt3gmyk5r2.1 ArrayExpress Data: Accession number E-MTAB-9365

cell biology↗

bioRxiv2021

Ciliary control of meiotic chromosomal pairing mechanics and germ cell morphogenesis

The hallmark of meiosis is chromosomal pairing and synapsis via synaptonemal complexes, but chromosomal pairing also depends on cytoplasmic counterparts that tether and rotate telomeres on the nuclear envelope. Telomeres slide on perinuclear microtubules, shuffling chromosomes and mechanically driving their homology searches. Pull of telomeres towards the centrosome drives formation of the "zygotene chromosomal bouquet". These telomere dynamics are essential for pairing and fertility, and the bouquet, discovered in 1900, is universally conserved. Nevertheless, how cytoplasmic counterparts of bouquet formation are mechanically regulated has remained enigmatic. Here, we report the "zygotene cilium" - a previously unrecognized cilium, in oocytes. We show in zebrafish that this cilium specifically connects to the bouquet centrosome, constituting a cable system of the cytoplasmic bouquet machinery. Furthermore, zygotene cilia extend throughout the germline cyst, a conserved germ cell organization. Using multiple ciliary mutants and laser-induced excision, we demonstrate that the zygotene cilium is essential for chromosomal bouquet and synaptonemal complex formation, germ cell morphogenesis, ovarian development and fertility. Mechanistically, we provide evidence that the cilium functions at least partly via anchoring the bouquet centrosome in order to counterbalance telomere rotation and pulling. We also show that the zygotene cilium is conserved in both male and female meiosis in zebrafish, as well as in mammals. Our work uncovers the novel concept of a cilium as a critical player in meiosis and sheds new light on reproduction phenotypes in ciliopathies. We propose a cellular paradigm that cilia can control chromosomal dynamics.

cell biology↗