| 1. |
- Cecchini, Katharine, et al.
(författare)
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The transcription factor TCFL5 responds to A-MYB to elaborate the male meiotic program in mice
- 2023
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Ingår i: Reproduction. - 1470-1626 .- 1476-3990. ; 165:2, s. 183-196
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Tidskriftsartikel (refereegranskat)abstract
- In male mice, the transcription factors STRA8 and MEISON initiate meiosis I. We report that STRA8/MEISON activates the transcription factors A-MYB and TCFL5, which together reprogram gene expression after spermatogonia enter into meiosis. TCFL5 promotes the transcription of genes required for meiosis, mRNA turnover, miR-34/449 production, meiotic exit, and spermiogenesis. This transcriptional architecture is conserved in rhesus macaque, suggesting TCFL5 plays a central role in meiosis and spermiogenesis in placental mammals. Tcfl5(em1/em1) mutants are sterile, and spermatogenesis arrests at the mid- or late-pachytene stage of meiosis. Moreover, Tcfl5(+/em1) mutants produce fewer motile sperm.
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| 2. |
- Hangen, Emilie, et al.
(författare)
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Interaction between AIF and CHCHD4 Regulates Respiratory Chain Biogenesis
- 2015
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Ingår i: Molecular cell. - : Elsevier BV. - 1097-4164 .- 1097-2765. ; 58:6, s. 1001-1014
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Tidskriftsartikel (refereegranskat)abstract
- Apoptosis-inducing factor (AIF) is a mitochondrial flavoprotein that, beyond its apoptotic function, is required for the normal expression of major respiratory chain complexes. Here we identified an AIF-interacting protein, CHCHD4, which is the central component of a redox-sensitive mitochondrial intermembrane space import machinery. Depletion or hypomorphic mutation of AIF caused a downregulation of CHCHD4 protein by diminishing its mitochondrial import. CHCHD4 depletion sufficed to induce a respiratory defect that mimicked that observed in AIF-deficient cells. CHCHD4 levels could be restored in AIF-deficient cells by enforcing its AIF-independent mitochondrial localization. This modified CHCHD4 protein reestablished respiratory function in AIF-deficient cells and enabled AIF-deficient embryoid bodies to undergo cavitation, a process of programmed cell death required for embryonic morphogenesis. These findings explain how AIF contributes to the biogenesis of respiratory chain complexes, and they establish an unexpected link between the vital function of AIF and the propensity of cells to undergo apoptosis.
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| 3. |
- Mou, Haiwei, et al.
(författare)
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CRISPR-induced exon skipping of β-catenin reveals tumorigenic mutants driving distinct subtypes of liver cancer
- 2023
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Ingår i: Journal of Pathology. - : Wiley. - 0022-3417 .- 1096-9896. ; 259:4, s. 415-427
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Tidskriftsartikel (refereegranskat)abstract
- CRISPR/Cas9-driven cancer modeling studies are based on the disruption of tumor suppressor genes by small insertions or deletions (indels) that lead to frame-shift mutations. In addition, CRISPR/Cas9 is widely used to define the significance of cancer oncogenes and genetic dependencies in loss-of-function studies. However, how CRISPR/Cas9 influences gain-of-function oncogenic mutations is elusive. Here, we demonstrate that single guide RNA targeting exon 3 of Ctnnb1 (encoding β-catenin) results in exon skipping and generates gain-of-function isoforms in vivo. CRISPR/Cas9-mediated exon skipping of Ctnnb1 induces liver tumor formation in synergy with YAPS127A in mice. We define two distinct exon skipping-induced tumor subtypes with different histological and transcriptional features. Notably, ectopic expression of two exon-skipped β-catenin transcript isoforms together with YAPS127A phenocopies the two distinct subtypes of liver cancer. Moreover, we identify similar CTNNB1 exon-skipping events in patients with hepatocellular carcinoma. Collectively, our findings advance our understanding of β-catenin-related tumorigenesis and reveal that CRISPR/Cas9 can be repurposed, in vivo, to study gain-of-function mutations of oncogenes in cancer.
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| 4. |
- Yu, Tiangxiong, et al.
(författare)
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A-MYB/TCFL5 regulatory architecture ensures the production of pachytene piRNAs in placental mammals
- 2023
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Ingår i: RNA. - : Cold Spring Harbor Laboratory. - 1355-8382 .- 1469-9001. ; 29:1, s. 30-43
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Tidskriftsartikel (refereegranskat)abstract
- In male mice, the transcription factor A-MYB initiates the transcription of pachytene piRNA genes during meiosis. Here, we report that A-MYB activates the transcription factor Tcfl5 produced in pachytene spermatocytes. Subsequently, A-MYB and TCFL5 reciprocally reinforce their own transcription to establish a positive feedback circuit that triggers pachytene piRNA production. TCFL5 regulates the expression of genes required for piRNA maturation and promotes transcription of evolutionarily young pachytene piRNA genes, whereas A-MYB activates the transcription of older pachytene piRNA genes. Intriguingly, pachytene piRNAs from TCFL5-dependent young loci initiate the production of piRNAs from A-MYB-dependent older loci, ensuring the self-propagation of pachytene piRNAs. A-MYB and TCFL5 act via a set of incoherent feedforward loops that drive regulation of gene expression by pachytene piRNAs during spermatogenesis. This regulatory architecture is conserved in rhesus macaque, suggesting that it was present in the last common ancestor of placental mammals.
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