Here are some of our publications!
for a complete list: Google Scholar | Pubmed
Thanks to progress in genomics, we know a lot about where Transcription Factors (TFs) bind, but what they do once bound remains poorly understood. Specifically, we wondered how TFs tune the dynamic properties of transcription. In collaboration with the labs of Mikko Taipale and Alex Holehouse, we discovered that TFs are kinetically specialized: some turn their target gene on, while others regulate how fast the gene is able to fire transcripts when on. Mining public protein-protein interaction databases, we developed a model that classifies arbitrary human TFs into kinetic families based on their known partners.
The Kinetic Landscape of Human Transcription Factors
Mamrak NE, Alerasool N, Griffith D, Holehouse AS, Taipale M & Lionnet T.* (2022)
* : corresponding author
A universal deep-learning model for zinc finger design enables transcription factor reprogramming
Ichikawa DM, Abdin O, Alerasool N, Kogenaru M, Mueller AL, Wen H, Giganti DO, Goldberg GW, Adams S, Spencer JM, Razavi R, Nim S, Zheng H, Gionco C, Clark FT, Strokach A, Hughes TR, Lionnet T, Taipale M, Kim PM* & Noyes MB* (2023)
* : corresponding author
Several models for drug resistance have been proposed, including the selection of pre-existing resistant clones or therapy-induced resistance through genetic and non-genetic mechanisms. In collaboration with the lab of Itai Yanai , we provide compelling evidence that the life history of the cancer cells – in terms of the treatment duration and the dose exposure – are crucial determinants in eliciting cancer resistance. We show that cancer cells adapt according to the selective pressures imposed by the therapy along an evolutionary trajectory that we call the ‘resistance continuum’, with distinct physiological responses unfolding over time, including both genetic and epigenetic contributions.
Drug-induced adaptation along a resistance continuum in cancer cells
Franca G, Baron M, Pour M, King BR, Rao A, Misirlioglu S, Barkley D, Dolgalev I, Tang KH, Avital G, Kuperwaser F, Patel A, Levine DA, Lionnet T* & Yanai I* (2022)
* : equal last authors
Despite an ever-expanding catalog of noncoding elements that are implicated in the control of mammalian gene expression, how the regulatory input from multiple elements is integrated across a genomic neighborhood has remained largely unclear. This challenge is exemplified at Hox clusters (~100 to 200 kb), which contain genes that specify positional identity along the anterior-posterior axis of the developing embryo. Taking inspiration from the bottom-up approaches of synthetic biology and biochemical reconstitution, the Mazzoni and Boeke labs synthesized large DNA constructs (>100 kb) that enable probing regulation at the scale of a native genomic neighborhood. The data suggest that the active gene and chromatin boundary specification at Hoxa in response to the developmental morphogen Retinoic Acid is primarily driven by internal transcription factor binding sites. Distal enhancers are dispensable for the specification of active genes but synergize with intracluster activator binding to boost the amount of transcription.
Synthetic regulatory reconstitution reveals principles of mammalian Hox cluster regulation
Pinglay S, Bulajic M, Rahe BP, Huang E, Brosh R, Mamrak NE, King BR, German S, Cadley JA, Rieber L, Easo N, Lionnet T, Mahony S, Maurano MT, Holt LJ, Mazzoni EO, Boeke JD (2022)
RS-FISH: Precise, interactive and scalable smFISH spot detection using Radial Symmetry
Bahry E#, Breimann L#, Epstein L#, Kolyvanov K, Harrington KIS*, Lionnet T*, Preibisch S*. (2021)
* : corresponding authors | # : equal contributions
BiorXiv | video walk through | Github | Nature Methods (in press)
Transcription factors contact chromatin very briefly (seconds!), but can form large clusters. How do these unique dynamics regulate transcription? In this review, we present the tools that enable these observations and discuss possible models. This piece is part of the upcoming “The Nucleus” textbook (2nd edition, editors Tom Misteli, Ana Pombo & Martin Hetzer).
Transcription Factor Dynamics
Lu F & Lionnet T. (2021)
Cold Spring Harbor Perspectives in Biology | pdf
Nucleosomes help package the DNA to a manageable size into the nucleus. Chromatin remodelers rearrange nucleosomes in order to maintain active genome regions open for business, and ensure that silenced genome regions remain tightly compacted. Here we show in collaboration with the Wu lab that chromatin remodelers perform their tasks during very brief time intervals (seconds). Combined with genomics data, these results suggest that the open chromatin regions in the genome emerge from brief and frequent interactions with multiple chromatin remodelers.
Single-molecule imaging of chromatin remodelers reveals role of ATPase in promoting fast kinetics of target search and dissociation from chromatin
Kim JM, Visanpattanasin P, Jou V, Liu S, Tang X, Zheng Q, Li KY, Snedeker J, Lavis LD, Lionnet T, Wu C (2021)
This review introduces live-cell single-molecule imaging technologies to a broad audience, and discusses what these new approaches – some of them developed by the lab – can teach us about transcription regulation.
Single-molecule tracking of transcription protein dynamics in living cells: seeing is believing, but what are we seeing?
Lionnet T, Wu C (2021)
Spatio-Temporal Coordination of Transcription Preinitiation Complex Assembly in Live Cells
Nguyen VQ, Ranjan A, Liu S, Tang X, Ling YH, Wisniewski J, Mizuguchi G, Li KY, Jou V, Zheng Q, Lavis LD, Lionnet T, Wu C. (2020)
The H2A.Z histone variant, a genome-wide hallmark of permissive chromatin, is enriched near transcription start sites in all eukaryotes. H2A.Z is deposited by the SWR1 chromatin remodeler and evicted by unclear mechanisms. We tracked H2A.Z in living yeast at single-molecule resolution, and found that H2A.Z eviction is dependent on RNA Polymerase II (Pol II) and the Kin28/Cdk7 kinase, which phosphorylates Serine 5 of heptapeptide repeats on the carboxy-terminal domain of the largest Pol II subunit Rpb1. These findings link H2A.Z eviction to transcription initiation, promoter escape and early elongation activities of Pol II. Because passage of Pol II through +1 nucleosomes genome-wide would obligate H2A.Z turnover, we propose that global transcription of noncoding RNAs prior to premature termination, in addition to transcription of mRNAs, are responsible for eviction of H2A.Z. Such usage of yeast Pol II suggests a general mechanism coupling eukaryotic transcription to erasure of the H2A.Z epigenetic signal.
Live-cell single particle imaging reveals the role of RNA polymerase II in histone H2A.Z eviction
Ranjan A, Nguyen VQ, Liu S, Wisniewski J, Kim JM, Tang X, Mizuguchi G, Elalaoui E, Nickels TJ, Jou V, English BP, Zheng Q, Luk E, Lavis LD, Lionnet T, Wu C. (2020)
The spatial organization of the genome inside the nucleus is known to impact gene expression, for instance through physical contacts between the promoter of a gene and a regulatory DNA sequence localized far away along the chromosome. How DNA folding impacts the expression of key cancer driving genes is unclear. Here, we characterize the interplay between DNA organization and gene expression in T cell acute lymphoblastic leukemia (T-ALL) cells, demonstrating a change in physical organization linked with cancer cells at the Myc locus, correlated with expression of the oncogene.
Dynamic 3D chromosomal landscapes in acute leukemia
Kloetgen K*, Thandapani P*, Ntziachristos P*, Ghebrechristos Y, Nomikou S, Lazaris C, Chen X, Hu H, Bakogianni S, Wang J, Fu Y, Boccalatte F, Zhong H, Paietta E, Trimarchi T, Zhu Y, van Vlierberghe P, Inghirami G, Lionnet T, Aifantis I and Tsirigos A. (2019) BiorXiv | Nature Genetics
Embryos initially contain parental mRNA and do not transcribe their own genes. They remain silent until the Zygotic Genome Activation, when the first genes are transcribed. How this happens, and how chromatin changes to favor the emergence of transcription remains unclear. This work demonstrates how fluorescently labeled antibody fragments (Fabs) can be used to track the changes in chromatin modifications that pave the way for the onset of transcription.
Histone H3K27 acetylation precedes active transcription during zebrafish zygotic genome activation as revealed by live-cell analysis
Sato Y, Hilbert L, Oda H, Wan Y, Heddleston JM, Chew TL, Zaburdaev V, Keller P, Lionnet T, Vastenhouw N, Kimura H.
(2019) Development 146, dev179127 | BiorXiv
mRNA quantification using single-molecule FISH in Drosophila embryos.
Trcek T, Lionnet T, Shroff H, Lehmann R.
(2017) Nature Protocols 12(7):1326-1348.
Quantitative mRNA Imaging Throughout the Entire Drosophila Brain
Long X*, Colonell J, Wong AM, Singer RH, Lionnet T*, (2017) Nature Methods 14(7):703-706; Bioarxiv
*Corresponding author
Bright photoactivatable fluorophores for single-molecule Imaging.
Grimm JB, English BP, Choi H, Muthusamy AK, Mehl BP, Dong P, Brown TA, Lippincott-Schwartz J, Liu Z, Lionnet T*, Lavis LD* (2016) Nature Methods doi:10.1038/nmeth.4034 Bioarxiv PMC
*Corresponding author
Real-time Quantification of single RNA translation dynamics in living cells.
Morisaki T, Lyon K, DeLuca KF, DeLuca JG, English BP, Zhang Z, Lavis LD, Grimm JB, Viswanathan S, Looger LL, Lionnet T, Stasevich T. (2016) Science Jun 17; 352 (6292): 1425-9
RNA Polymerase II cluster dynamics predicts mRNA ouput in living cells.
Cho WK, Jayanth N, English BP, Inoue T, Andrews JO, Conway W, Grimm JB, Spille JH, Lavis LD, Lionnet T*, Cisse II* (2016) eLife PMC
*Corresponding author
Multifocus microscopy with precise color multi-phase diffractive optics applied in functional neuronal imaging.
Abrahamsson S, Ilic R, Wisniewski J, Mehl B, Yu L, Chen L, Davanco M, Oudjedi L, Fiche J-B, Hajj B, Jin X, Pulupa J, Cho C, Mir M, El Beheiry M, Darzacq X, Nollmann M, Dahan M, Wu C, Lionnet T, Liddle AJ, Bargmann CI (2016) Biomedical Optics Express 7 (3) 855 PMC
Mapping translation ‘hot spots’ in live cells by tracking single molecules of mRNA and ribosomes.
Katz ZB, English BP, Lionnet T, Yoon YJ, Monnier N, Ovryn B, Bathe M, Singer RH. (2016) eLife 10415 PMC
CASFISH : CRISPR/Cas9-mediated in situ labeling of genomic loci in fixed cells.
Deng W, Shi X, Tjian R, Lionnet T, Singer RH. (2015) Proc. Natl. Acad. Sci., 112 (38), 11870-11875 PMC
Drosophila germ granules are structured and contain homotypic mRNA clusters.
Treck T, Grosch M, York A, Shroff H, Lionnet T, Lehman R. (2015) Nature Communications, 6:7962 PMC
Cellular Levels of Signaling Factors Are Sensed by β-actin Alleles to Modulate Transcriptional Pulse Intensity.
Kalo A, Kanter I, Shraga A, Sheinberger J, Tzemach H, Kinor N, Singer RH, Lionnet T, Shav-Tal Y. (2015) Cell Reports 11(3) 419-32 PMC
An RNA biosensor for imaging the first round of translation from single cells to living animals.
Halstead JM*, Lionnet T*, Wilbertz JH*, Wippich F*, Ephrussi A, Singer RH, Chao JA. (2015) Science 347(6228) 1367-671 PMC
*Equal Contributions
A general method to improve fluorophores for live-cell and single-molecule microscopy.
Grimm JB, English BP, Chen J, Slaughter JP, Zhang Z, Revyakin A, Patel R, Macklin JJ, Normanno D, Singer RH, Lionnet T*, Lavis LD.* (2015) Nature Methods 12(3) 244-50 PMC
*Corresponding author
Single-molecule dynamics of enhanceosome assembly in embryonic stem cells.
Chen J, Zhang Z, Li L, Chen BC, Revyakin A, Hajj B, Legant W, Dahan M, Lionnet T, Betzig E, Tjian R, Liu Z. (2014) Cell 156 (6) 1274-85 PMC
Colocalization of different influenza viral RNA segments in the cytoplasm before viral budding as shown by single-molecule sensitivity FISH analysis.
Chou YY, Heaton NS, Gao Q, Palese P, Singer R, Lionnet T.* (2013) PLoS Pathogens, 9 (5) e1003358 PMC
- Corresponding Author
Transcription goes digital.
Lionnet T, Singer RH (2012). Embo Reports, 13(4):313-21 PMC
Spatial arrangement of conserved recognition elements identifies RNA regulatory networks.
Patel VL, Mitra S, Harris R, Buxbaum AR, Lionnet T, Girvin M, Levy M, Almo SC, Brenowitz M, Singer RH, Chao JA. (2012) Genes & Development, 26 (1) 43-53; PMC
A transgenic mouse for in vivo detection of endogenous labeled mRNA.
Lionnet T, Czaplinski K, Darzacq X, Shav-Tal Y, Wells AL, Chao JA, Park HY, de Turris V, Lopez-Jones M, Singer RH (2011). Nature Methods, 8(2) 165-70 PMC
Transcription of functionally related genes is not coordinated.
Gandhi SJ, Zenklusen D, Lionnet T, Singer RH (2011). Nature Structural & Molecular Biology, 18 (1) 27-34 PMC
Real-time observation of bacteriophage T4 gp41 helicase reveals an unwinding mechanism.
Lionnet T, Spiering MM, Benkovic SJ, Bensimon D, Croquette V (2007). Proc. Natl. Acad. Sci. 104 (50): 19790-5 PMC
Sequence dependent twist-stretch coupling in DNA.
Lionnet T, Lankas F (2007). Biophys. J. 92 (4): L30-32 PMC
Wringing out DNA.
Lionnet T, Joubaud S, Lavery R, Bensimon D, Croquette V (2006). Phys. Rev. Lett., 96 (17): 178102 PMC
Single-molecule assay reveals strand switching and enhanced processivity of UvrD.
Dessinges MN, Lionnet T, Xi XG, Bensimon D, Croquette V (2004). Proc. Natl. Acad. Sci. 101 (17): 6439-44 PMC