TY - JOUR
T1 - Ceg1 depletion reveals mechanisms governing degradation of non-capped RNAs in Saccharomyces cerevisiae
AU - Zanin, Onofrio
AU - Eastham, Matthew
AU - Winczura, Kinga
AU - Ashe, Mark
AU - Martinez-Nunez, Rocio t.
AU - Hebenstreit, Daniel
AU - Grzechnik, Pawel
PY - 2023/11/2
Y1 - 2023/11/2
N2 - Most functional eukaryotic mRNAs contain a 5′ 7-methylguanosine (m
7G) cap. Although capping is essential for many biological processes including mRNA processing, export and translation, the fate of uncapped transcripts has not been studied extensively. Here, we employed fast nuclear depletion of the capping enzymes in Saccharomyces cerevisiae to uncover the turnover of the transcripts that failed to be capped. We show that although the degradation of cap-deficient mRNA is dominant, the levels of hundreds of non-capped mRNAs increase upon depletion of the capping enzymes. Overall, the abundance of non-capped mRNAs is inversely correlated to the expression levels, altogether resembling the effects observed in cells lacking the cytoplasmic 5′−3′ exonuclease Xrn1 and indicating differential degradation fates of non-capped mRNAs. The inactivation of the nuclear 5′−3′ exonuclease Rat1 does not rescue the non-capped mRNA levels indicating that Rat1 is not involved in their degradation and consequently, the lack of the capping does not affect the distribution of RNA Polymerase II on the chromatin. Our data indicate that the cap presence is essential to initiate the Xrn1-dependent degradation of mRNAs underpinning the role of 5′ cap in the Xrn1-dependent buffering of the cellular mRNA levels.
AB - Most functional eukaryotic mRNAs contain a 5′ 7-methylguanosine (m
7G) cap. Although capping is essential for many biological processes including mRNA processing, export and translation, the fate of uncapped transcripts has not been studied extensively. Here, we employed fast nuclear depletion of the capping enzymes in Saccharomyces cerevisiae to uncover the turnover of the transcripts that failed to be capped. We show that although the degradation of cap-deficient mRNA is dominant, the levels of hundreds of non-capped mRNAs increase upon depletion of the capping enzymes. Overall, the abundance of non-capped mRNAs is inversely correlated to the expression levels, altogether resembling the effects observed in cells lacking the cytoplasmic 5′−3′ exonuclease Xrn1 and indicating differential degradation fates of non-capped mRNAs. The inactivation of the nuclear 5′−3′ exonuclease Rat1 does not rescue the non-capped mRNA levels indicating that Rat1 is not involved in their degradation and consequently, the lack of the capping does not affect the distribution of RNA Polymerase II on the chromatin. Our data indicate that the cap presence is essential to initiate the Xrn1-dependent degradation of mRNAs underpinning the role of 5′ cap in the Xrn1-dependent buffering of the cellular mRNA levels.
KW - Exonucleases/metabolism
KW - RNA Caps/genetics
KW - RNA, Messenger/genetics
KW - Saccharomyces cerevisiae Proteins/genetics
KW - Saccharomyces cerevisiae/genetics
UR - http://www.scopus.com/inward/record.url?scp=85175693831&partnerID=8YFLogxK
UR - https://www.mendeley.com/catalogue/14a41424-b302-31ba-89f9-c24f315637ec/
U2 - 10.1038/s42003-023-05495-6
DO - 10.1038/s42003-023-05495-6
M3 - Article
C2 - 37919390
SN - 2399-3642
VL - 6
JO - Communications Biology
JF - Communications Biology
IS - 1
M1 - 1112
ER -