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Translational repression of NMD targets by GIGYF2 and EIF4E2

ABSTRACT: Translation of messenger RNAs (mRNAs) with premature translation termination codons produces truncated proteins with potentially deleterious effects. This is prevented by nonsense-mediated mRNA decay (NMD) of these mRNAs. NMD is triggered by ribosomes terminating upstream of a splice site marked by an exon-junction complex (EJC), but also acts on many mRNAs lacking a splice junction after their termination codon. We developed a genome-wide CRISPR flow cytometry screen to identify regulators of mRNAs with premature termination codons in K562 cells. This screen recovered essentially all core NMD factors and suggested a role for EJC factors in degradation of PTCs without downstream splicing. Among the strongest hits were the translational repressors GIGYF2 and EIF4E2. GIGYF2 and EIF4E2 mediate translational repression but not mRNA decay of a subset of NMD targets and interact with NMD factors genetically and physically. Our results suggest a model wherein recognition of a stop codon as premature can lead to its translational repression through GIGYF2 and EIF4E2.

INSTRUMENT(S): Q Exactive HF

ORGANISM(S): Homo Sapiens (human)

TISSUE(S): Permanent Cell Line Cell

SUBMITTER: Niladri Sinha

LAB HEAD: Rachel Green

PROVIDER: PXD027479 | Pride | 2021-10-12

REPOSITORIES: Pride

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			Action	DRS
	Figure6-RAW-files-indices.xlsx	Xlsx
	LD-QC-LE_201207_GreenR_NS_S10_20210129063811.mgf	Mgf
	LD-QC-LE_201207_GreenR_NS_S10_20210129063811.raw	Raw
	LD-QC-LE_201207_GreenR_NS_S11_20210129103048.mgf	Mgf
	LD-QC-LE_201207_GreenR_NS_S11_20210129103048.raw	Raw

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Project description:Translation of messenger RNAs (mRNAs) with premature translation termination codons produces truncated proteins with potentially deleterious effects. This is prevented by nonsense-mediated mRNA decay (NMD) of these mRNAs. NMD is triggered by ribosomes terminating upstream of a splice site marked by an exon-junction complex (EJC), but also acts on many mRNAs lacking a splice junction after their termination codon. We developed a genome-wide CRISPR flow cytometry screen to identify regulators of mRNAs with premature termination codons in K562 cells. This screen recovered essentially all core NMD factors and suggested a role for EJC factors in degradation of PTCs without downstream splicing. Among the strongest hits were the translational repressors GIGYF2 and EIF4E2. GIGYF2 and EIF4E2 mediate translational repression but not mRNA decay of a subset of NMD targets and interact with NMD factors genetically and physically. Our results suggest a model wherein recognition of a stop codon as premature can lead to its translational repression through GIGYF2 and EIF4E2.

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