Robust elimination of genome-damaged cells safeguards against brain somatic aneuploidy following Knl1 deletion
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ABSTRACT:
PROVIDER: PRJNA473324 | ENA |
REPOSITORIES: ENA
Dataset's files
| Action | DRS | |||
|---|---|---|---|---|
| SRR7224840.fastq.gz | Fastqsanger.gz | |||
| SRR7224850.fastq.gz | Fastqsanger.gz | |||
| SRR7224841.fastq.gz | Fastqsanger.gz | |||
| SRR7224851.fastq.gz | Fastqsanger.gz | |||
| SRR7224842.fastq.gz | Fastqsanger.gz |
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Project description:The brain is a genomic mosaic shaped by cellular responses to genome damage. Here, we manipulate somatic genome stability by conditional Knl1 deletion from embryonic mouse brain. KNL1 mutations cause microcephaly and KNL1 mediates the spindle assembly checkpoint, a safeguard against chromosome missegregation and aneuploidy. We find that following Knl1 deletion, segregation errors in mitotic neural progenitor cells give rise to DNA damage on the missegregated chromosomes. This triggers rapid p53 activation and robust apoptotic and microglial phagocytic responses that extensively eliminate cells with somatic genome damage, thus causing microcephaly. By leaving only karyotypically normal progenitors to continue dividing, these mechanisms provide a second safeguard against brain somatic aneuploidy. Without Knl1 or p53-dependent safeguards, genome-damaged cells are not cleared, alleviating microcephaly, but paradoxically leading to total pre-weaning lethality. Thus, mitotic genome damage activates robust responses to eliminate somatic mutant cells, which if left unpurged, can impact brain and organismal fitness.
2019-05-25 | GSE114956 | GEO
Project description:The brain is a genomic mosaic shaped by cellular responses to genome damage. Here, we manipulate somatic genome stability by conditional Knl1 deletion from embryonic mouse brain. KNL1 mutations cause microcephaly and KNL1 mediates the spindle assembly checkpoint, a safeguard against chromosome missegregation and aneuploidy. We find that following Knl1 deletion, segregation errors in mitotic neural progenitor cells give rise to DNA damage on the missegregated chromosomes. This triggers rapid p53 activation and robust apoptotic and microglial phagocytic responses that extensively eliminate cells with somatic genome damage, thus causing microcephaly. By leaving only karyotypically normal progenitors to continue dividing, these mechanisms provide a second safeguard against brain somatic aneuploidy. Without Knl1 or p53-dependent safeguards, genome-damaged cells are not cleared, alleviating microcephaly, but paradoxically leading to total pre-weaning lethality. Thus, mitotic genome damage activates robust responses to eliminate somatic mutant cells, which if left unpurged, can impact brain and organismal fitness.
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Project description:In all primary cells analyzed to date, aneuploidy is associated with poor proliferation. Yet, how abnormal karyotypes affect cancer – a disease characterized by both aneuploidy and heightened proliferative capacity – is largely unknown. Here, I demonstrate that the transcriptional alterations caused by aneuploidy in primary cells are also present in chromosomally-unstable cancer cell lines, but are not common to all aneuploid cancers. Moreover, chromosomally-unstable cancer lines display increased glycolytic and TCA-cycle flux, as is also observed in primary aneuploid cells. The biological response to aneuploidy is associated with cellular stress and slow proliferation, and a 70-gene signature derived from primary aneuploid cells is a strong predictor of increased survival in several cancers. Inversely, a transcriptional signature derived from clonal aneuploidy in tumors correlates with high mitotic activity and poor prognosis. I speculate that there are two types of aneuploidy in cancer: clonal aneuploidy, which is selected during tumor evolution and is associated with robust growth, and sub-clonal aneuploidy, which is caused by chromosomal instability (CIN) and more closely resembles the stressed state of primary aneuploid cells. Nonetheless, CIN is not benign: a subset of genes upregulated in high-CIN cancers predict aggressive disease in human patients in a proliferation-independent manner.
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