1
|
Lu X, Liu L. Genome stability from the perspective of telomere length. Trends Genet 2024; 40:175-186. [PMID: 37957036 DOI: 10.1016/j.tig.2023.10.013] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2023] [Revised: 10/20/2023] [Accepted: 10/23/2023] [Indexed: 11/15/2023]
Abstract
Telomeres and their associated proteins protect the ends of chromosomes to maintain genome stability. Telomeres undergo progressive shortening with each cell division in mammalian somatic cells without telomerase, resulting in genome instability. When telomeres reach a critically short length or are recognized as a damage signal, cells enter a state of senescence, followed by cell cycle arrest, programmed cell death, or immortalization. This review provides an overview of recent advances in the intricate relationship between telomeres and genome instability. Alongside well-established mechanisms such as chromosomal fusion and telomere fusion, we will delve into the perspective on genome stability by examining the role of retrotransposons. Retrotransposons represent an emerging pathway to regulate genome stability through their interactions with telomeres.
Collapse
Affiliation(s)
- Xinyi Lu
- State Key Laboratory of Medicinal Chemical Biology, Nankai University, Tianjin, Tianjin 300350, China.
| | - Lin Liu
- State Key Laboratory of Medicinal Chemical Biology, Nankai University, Tianjin, Tianjin 300350, China; Frontiers Science Center for Cell Responses, College of Life Science, Nankai University, Tianjin, Tianjin 300071, China; Haihe Laboratory of Cell Ecosystem, Chinese Academy of Medical Sciences and Peking Union Medical College, Tianjin 300020, China; Institute of Translational Medicine, Tianjin Union Medical Center, Nankai University, Tianjin 300000, China.
| |
Collapse
|
2
|
Lu X. Regulation of endogenous retroviruses in murine embryonic stem cells and early embryos. J Mol Cell Biol 2024; 15:mjad052. [PMID: 37604781 PMCID: PMC10794949 DOI: 10.1093/jmcb/mjad052] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Revised: 11/24/2022] [Accepted: 08/19/2023] [Indexed: 08/23/2023] Open
Abstract
Endogenous retroviruses (ERVs) are important components of transposable elements that constitute ∼40% of the mouse genome. ERVs exhibit dynamic expression patterns during early embryonic development and are engaged in numerous biological processes. Therefore, ERV expression must be closely monitored in cells. Most studies have focused on the regulation of ERV expression in mouse embryonic stem cells (ESCs) and during early embryonic development. This review touches on the classification, expression, and functions of ERVs in mouse ESCs and early embryos and mainly discusses ERV modulation strategies from the perspectives of transcription, epigenetic modification, nucleosome/chromatin assembly, and post-transcriptional control.
Collapse
Affiliation(s)
- Xinyi Lu
- State Key Laboratory of Medicinal Chemical Biology, Nankai University, Tianjin 300350, China
| |
Collapse
|
3
|
Tam PLF, Leung D. The Molecular Impacts of Retrotransposons in Development and Diseases. Int J Mol Sci 2023; 24:16418. [PMID: 38003607 PMCID: PMC10671454 DOI: 10.3390/ijms242216418] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2023] [Revised: 11/11/2023] [Accepted: 11/14/2023] [Indexed: 11/26/2023] Open
Abstract
Retrotransposons are invasive genetic elements that constitute substantial portions of mammalian genomes. They have the potential to influence nearby gene expression through their cis-regulatory sequences, reverse transcription machinery, and the ability to mold higher-order chromatin structures. Due to their multifaceted functions, it is crucial for host fitness to maintain strict regulation of these parasitic sequences to ensure proper growth and development. This review explores how subsets of retrotransposons have undergone evolutionary exaptation to enhance the complexity of mammalian genomes. It also highlights the significance of regulating these elements, drawing on recent studies conducted in human and murine systems.
Collapse
Affiliation(s)
- Phoebe Lut Fei Tam
- Division of Life Science, The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong SAR, China;
| | - Danny Leung
- Division of Life Science, The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong SAR, China;
- Center for Epigenomics Research, The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong SAR, China
| |
Collapse
|
4
|
Zhao X, Li X, Sun H, Zhao X, Gao T, Shi P, Chen F, Liu L, Lu X. Dot1l cooperates with Npm1 to repress endogenous retrovirus MERVL in embryonic stem cells. Nucleic Acids Res 2023; 51:8970-8986. [PMID: 37522386 PMCID: PMC10516645 DOI: 10.1093/nar/gkad640] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2022] [Revised: 07/06/2023] [Accepted: 07/20/2023] [Indexed: 08/01/2023] Open
Abstract
Dot1l is a histone methyltransferase without a SET domain and is responsible for H3K79 methylation, which marks active transcription. In contradiction, Dot1l also participates in silencing gene expression. The target regions and mechanism of Dot1l in repressing transcription remain enigmatic. Here, we show that Dot1l represses endogenous retroviruses in embryonic stem cells (ESCs). Specifically, the absence of Dot1l led to the activation of MERVL, which is a marker of 2-cell-like cells. In addition, Dot1l deletion activated the 2-cell-like state and predisposed ESCs to differentiate into trophectoderm lineage. Transcriptome analysis revealed activation of 2-cell genes and meiotic genes by Dot1l deletion. Mechanistically, Dot1l interacted with and co-localized with Npm1 on MERVL, and depletion of Npm1 similarly augmented MERVL expression. The catalytic activity and AT-hook domain of Dot1l are important to suppress MERVL. Notably, Dot1l-Npm1 restricts MERVL by regulating protein level and deposition of histone H1. Furthermore, Dot1l is critical for Npm1 to efficiently interact with histone H1 and inhibit ubiquitination of H1 whereas Npm1 is essential for Dot1l to interact with MERVL. Altogether, we discover that Dot1l represses MERVL through chaperoning H1 by collaborating with Npm1. Importantly, our findings shed light on the non-canonical transcriptional repressive role of Dot1l in ESCs.
Collapse
Affiliation(s)
- Xin Zhao
- State Key Laboratory of Medicinal Chemical Biology, Nankai University, Tianjin, Tianjin 300350, China
| | - Xiaomin Li
- State Key Laboratory of Medicinal Chemical Biology, Nankai University, Tianjin, Tianjin 300350, China
| | - Haiyang Sun
- State Key Laboratory of Medicinal Chemical Biology, Nankai University, Tianjin, Tianjin 300350, China
| | - Xuan Zhao
- State Key Laboratory of Medicinal Chemical Biology, Nankai University, Tianjin, Tianjin 300350, China
| | - Tingting Gao
- State Key Laboratory of Medicinal Chemical Biology, Nankai University, Tianjin, Tianjin 300350, China
| | - Panpan Shi
- State Key Laboratory of Medicinal Chemical Biology, College of Life Science, Nankai University, Tianjin, Tianjin 300071, China
| | - Fuquan Chen
- State Key Laboratory of Medicinal Chemical Biology, College of Life Science, Nankai University, Tianjin, Tianjin 300071, China
| | - Lin Liu
- State Key Laboratory of Medicinal Chemical Biology, College of Life Science, Nankai University, Tianjin, Tianjin 300071, China
| | - Xinyi Lu
- State Key Laboratory of Medicinal Chemical Biology, Nankai University, Tianjin, Tianjin 300350, China
| |
Collapse
|
5
|
Cuttini E, Goi C, Pellarin E, Vida R, Brancolini C. HDAC4 in cancer: A multitasking platform to drive not only epigenetic modifications. Front Mol Biosci 2023; 10:1116660. [PMID: 36762207 PMCID: PMC9902726 DOI: 10.3389/fmolb.2023.1116660] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2022] [Accepted: 01/09/2023] [Indexed: 01/25/2023] Open
Abstract
Controlling access to genomic information and maintaining its stability are key aspects of cell life. Histone acetylation is a reversible epigenetic modification that allows access to DNA and the assembly of protein complexes that regulate mainly transcription but also other activities. Enzymes known as histone deacetylases (HDACs) are involved in the removal of the acetyl-group or in some cases of small hydrophobic moieties from histones but also from the non-histone substrate. The main achievement of HDACs on histones is to repress transcription and promote the formation of more compact chromatin. There are 18 different HDACs encoded in the human genome. Here we will discuss HDAC4, a member of the class IIa family, and its possible contribution to cancer development.
Collapse
Affiliation(s)
- Emma Cuttini
- Scuola Superiore Universitaria di Toppo Wassermann, Università degli Studi di Udine, Udine, Italy
| | - Camilla Goi
- Scuola Superiore Universitaria di Toppo Wassermann, Università degli Studi di Udine, Udine, Italy
| | - Ester Pellarin
- Scuola Superiore Universitaria di Toppo Wassermann, Università degli Studi di Udine, Udine, Italy
| | - Riccardo Vida
- Scuola Superiore Universitaria di Toppo Wassermann, Università degli Studi di Udine, Udine, Italy
| | - Claudio Brancolini
- Scuola Superiore Universitaria di Toppo Wassermann, Università degli Studi di Udine, Udine, Italy,Laboratory of Epigenomics, Department of Medicine, Università degli Studi di Udine, Udine, Italy,*Correspondence: Claudio Brancolini,
| |
Collapse
|