Zinc finger proteins (ZNF), a unique yet diverse group of proteins, play pivotal roles in fundamental cellular mechanisms including transcription regulation, chromatin remodeling, protein/RNA homeostasis, and DNA repair. Consequently, the mis regulation of ZNF proteins can result in a variety of human diseases, ranging from neurodevelopmental disorders to several cancers. Considering the promising results of DNA damage repair (DDR) inhibition in the clinic, as a therapeutic strategy for patients with homologous recombination (HR) deficiency, identifying other potential targetable DDR proteins as emerged vulnerabilities in resistant tumor cells is essential, especially when considering the burden of acquired drug resistance. Importantly, there are a growing number of studies identifying new ZNFs and revealing their significance in several DDR pathways, highlighting their great potential as new targets for DDR-inhibition therapy. Although, there are still many uncharacterized ZNF-containing proteins with unknown biological function. In this review, we highlight the major classes and observed biological functions of ZNF proteins in mammalian cells. We briefly introduce well-known and newly discovered ZNFs and describe their molecular roles and contributions to human health and disease, especially cancer. Finally, we discuss the significance of ZNFs in DNA repair mechanisms, their potential in cancer therapy and advances in exploiting ZNF proteins as future therapeutic targets for human disease.

DNA double strand break repair (DSBR) represents a fundamental process required to maintain genome stability and prevent the onset of disease. Whilst cell cycle phase and the chromatin context largely dictate which repair pathway is utilised to restore damaged DNA, it has been recently shown that nuclear actin filaments play a major role in clustering DNA breaks to facilitate DSBR by homologous recombination (HR). However, the mechanism with which nuclear actin and the different actin nucleating factors regulate HR is unclear. Interestingly, patients with biallelic mutations in the actin nucleating factor DIAPH1 exhibit a striking overlap of clinical features with the HR deficiency disorders, Nijmegen Breakage Syndrome (NBS) and Warsaw Breakage Syndrome (WABS). This suggests that DIAPH1 may play a role in regulating HR and that some of the clinical deficits associated with DIAPH1 mutations may be caused by an underlying DSBR defect. In keeping with this clinical similarity, we demonstrate that cells from DIAL (DIAPH1 Loss-of-function) Syndrome patients display an HR repair defect comparable to loss of NBS1. Moreover, we show that this DSBR defect is also observed in a subset of patients with Baraitser-Winter Cerebrofrontofacial (BWCFF) syndrome associated with mutations in ACTG1 (γ-actin) but not ACTB (β-actin). Lastly, we demonstrate that DIAPH1 and γ-actin promote HR-dependent repair by facilitating the relocalisation of the MRE11/RAD50/NBS1 complex to sites of DNA breaks to initiate end-resection. Taken together, these data provide a mechanistic explanation for the overlapping clinical symptoms exhibited by patients with DIAL syndrome, BWCFF syndrome and NBS.

Chromatin architecture is a central determinant of genomic stability. Effective DNA repair requires dynamic chromatin remodeling to grant repair factors timely access to lesions and to orchestrate repair pathway choice. Disruption of chromatin-regulatory mechanisms or DNA damage response pathways undermines repair fidelity and contributes to a wide spectrum of human disorders, including developmental syndromes, premature aging, and multiple cancers. Here, we review how chromatin state and remodeling complexes shape detection, signaling, and resolution of DNA double-strand breaks, and we examine how their misregulation drives disease and presents opportunities for therapeutic intervention. Specifically, we discuss how post-translational modifications and ATP-dependent chromatin remodeling complexes contribute to DNA damage repair with a particular focus on DNA double-strand breaks, one of the most deleterious DNA lesions. We summarize how chromatin remodeling and histone post-translational modifications regulate DNA repair pathway choice, and how these processes are essential for safeguarding genomic integrity and preventing human disease. Finally, we discuss emerging concepts and major unanswered questions in the context of chromatin function and DNA double-strand break repair, with a focus on exploring the emerging literature on the role of chromatin compartments and topological associated domains for orchestrating DNA repair within chromatin and safeguarding genomic stability.