Resf1, also known as Retroelement silencing factor 1, has multiple important functions. It is involved in transcriptional control, retroelement silencing, and plays a role in the regulation of pluripotent stem cells and germ cell specification [1,2,3]. Genetic models like KO mouse models are valuable for studying its functions.

In triple negative breast cancer, CRISPR or gene trap mouse models crossed to MMTV-PyMT showed that reduction of Resf1 led to increased tumor growth, shortened survival, and more lung metastases, indicating it is a tumor suppressor. Mechanistically, it may be involved in transcriptional control via association with compound G4 quadruplexes [1]. In embryonic stem cells, Resf1 knockout reduced self-renewal potential and the efficiency of differentiation into primordial germ cell-like cells [2]. A CRISPR knockout screen in mouse embryonic stem cells identified Resf1 as a novel molecule in retroelement silencing, where it regulates repressive epigenetic modifications associated with SETDB1 [3].

In conclusion, Resf1 is crucial for maintaining normal cell function in processes such as stem cell self-renewal, germ cell specification, and retroelement silencing. Its loss-of-function in KO mouse models reveals its tumor-suppressing role in triple negative breast cancer, highlighting its significance in understanding cancer biology and potentially developing new therapeutic strategies [1,2,3].

References:

1. Majocha, Megan R, Jackson, Devin E, Ha, Ngoc-Han, Lee, Maxwell P, Hunter, Kent W. 2024. Resf1 is a compound G4 quadruplex-associated tumor suppressor for triple negative breast cancer. In PLoS genetics, 20, e1011236. doi:10.1371/journal.pgen.1011236. https://pubmed.ncbi.nlm.nih.gov/38722825/

2. Vojtek, Matúš, Chambers, Ian. 2021. Loss of Resf1 reduces the efficiency of embryonic stem cell self-renewal and germline entry. In Life science alliance, 4, . doi:10.26508/lsa.202101190. https://pubmed.ncbi.nlm.nih.gov/34607919/

3. Fukuda, Kei, Okuda, Akihiko, Yusa, Kosuke, Shinkai, Yoichi. 2018. A CRISPR knockout screen identifies SETDB1-target retroelement silencing factors in embryonic stem cells. In Genome research, 28, 846-858. doi:10.1101/gr.227280.117. https://pubmed.ncbi.nlm.nih.gov/29728365/