Our aim is to understand how chromatin is replicated to ensure faithful transmission of both genetic and epigenetic information during mitotic cell division.
Inheritance of both DNA sequence and its organization into chromatin is fundamental for normal development and disease avoidance, because the stability and function of eukaryotic genomes is closely linked to chromatin structure. Nucleosomes, the building blocks of chromatin, are composed of two copies each of histones H3, H4, H2A, and H2B that can carry an array of different post-translational modifications (PTMs). These ‘tags’, often in specific combinations, regulate the transcriptional activity of underlying genes and play key roles in cellular differentiation and organismal development. Cancer cells show widespread alterations of DNA and histone modifications, which can jeopardize cellular memory and disable tumour suppressor functions. It is therefore central to understand mechanisms that maintain chromatin states during the cell cycle and unveil whether they go awry in cancer. In S phase of the cell cycle, the entire genome must be accurately replicated and the chromatin landscape reproduced on new DNA. The main focus of our research is to understand molecularly how chromatin is duplicated to ensure faithful transmission of both genetic and epigenetic information during cell division.
Our focus research areas are:
1. Histone Dynamics & Replication Control
We use state-of-the-art biochemistry and a wide-range of cell-based methods including advanced imaging to study replication-coupled histone dynamics. This includes pathways controlling delivery of newly synthesized histones and the enigmatic mechanisms underlying parental histone recycling. An entry point in this line of research is the histone H3-H4 chaperone Asf1, its interactions with the MCM2-7 helicase and regulation by Tousled like kinases.
We are also interested in how DNA synthesis is coordinated with histone supply and nucleosome assembly, because proper nucleosome packaging is central to genome stability and maintenance of its epigenetic fabric. Along this line, we investigate how replication associated DNA damage influences the chromatin landscape to unveil whether replication stress contributes to epigenetic instability in carcinogenesis.
2. Chromatin Replication & Epigenome Maintenance
We are taking genomic and proteomic approaches to identify new molecular mechanisms orchestrating chromatin replication in human cells. To follow chromatin dynamics through the cell cycle, we are developing approaches for large-scale isolation and proteomic analysis of chromatin. In parallel, we use automated high-throughput functional siRNA screens to identify new factors involved in chromatin replication (see example below). These complementary strategies provide potent means to unveil and dissect molecular processes implicated in chromatin duplication.
Klimovskaia IM, Young C, Strømme CB, Menard P, Jasencakova Z, Mejlvang J, Ask K, Ploug M, Nielsen ML, Jensen ON, Groth A. Tousled-like kinases phosphorylate Asf1 to promote histone supply during DNA replication. Nat Commun. 2014 Mar 6;5:3394.
Alabert C, Bukowski-Wills JC, Lee SB, Kustatscher G, Nakamura K, de Lima Alves F, Menard P, Mejlvang J, Rappsilber J, Groth A. Nascent chromatin capture proteomics determines chromatin dynamics during DNA replication and identifies unknown fork components. Nat Cell Biol. 2014, Feb 23,
Mejlvang J, Feng Y, Alabert C, Neelsen KJ, Jasencakova Z, Zhao X, Lees M, Sandelin A, Pasero P, Lopes M, Groth A. New histone supply regulates replication fork speed and PCNA unloading. J Cell Biol. 2014 Jan 6;204(1):29-43.
Ask K, Jasencakova Z, Menard P, Feng Y, Almouzni G, Groth A (2012). Codanin-1, mutated in the anaemic disease CDAI, regulates Asf1 function in S-phase histone supply.
Alabert C, Groth A (2012) Chromatin replication and epigenome maintenance. Nat Rev Mol Cell Biol 13:153-167
Duro E, Lundin C, Ask K, Sanchez-Pulido L, MacArtney TJ, Toth R, Ponting CP,
Groth A, Helleday T, Rouse J (2010). Identification of the MMS22L-TONSL complex that
promotes homologous recombination. Mol Cell. 2010 Nov 24;40(4):632-44.
Jasencakova Z, Groth A (2010). Replication stress, a source of epigenetic aberrations
in cancer? Bioessays Oct;32(10):847-55.
Jasencakova Z, Scharf AN, Ask K, Corpet A, Imhof A, Almouzni G, Groth A (2010). Replication Stress Interferes with Histone Recycling and Predeposition Marking of New Histones. Mol Cell. 2010 Mar 12;37(5):736-743.
Jasencakova Z, Groth A (2010). Restoring chromatin after replication: How new and old histone marks come together. Semin Cell Dev Biol. 2010 Apr;21(2):231-7. Review.
Groth A (2009). Replicating chromatin: a tale of histones. Biochem Cell Biol 87(1):51-63. Review.
Jasencakova Z. & Groth A (2008). Purification of multiprotein complexes using OneStrep technology. Epigenome Network of Excellence Online Protocols/ProtID41.
Groth A, Corpet A, Cook A, Roche D, Bartek J, Lukas J, Almouzni G (2007). Regulation of replication fork progression by histone supply/ demand. Science. 318:1928-31
Groth A, Rocha W, Verreault A, Almouzni G (2007). Chromatin challenges during DNA replication and repair. Cell 128:721-33
Groth A, Quivy J-P, Ray-Gallet D, Lukas J, Bartek J, Almouzni G (2005). Human Asf1 regulates the flow of S-phase histones in response to replicational stress. Mol Cell 17:301-11
Groth A, Lukas J, Nigg EA, Siljé HWH, Bartek J and Hansen K (2003). Human Tousled like kinases are targeted by an ATM- and Chkl-dependt DNA damage checkpoint. EMBO J 22:1676-87