Project description:microRNAs (miRNAs) associating with Argonaute proteins (AGOs) regulate gene expression in mammals. miRNA 3' ends are subject to frequent sequence modifications, which have been proposed to affect miRNA stability. However, the underlying mechanism is not well understood. Here, by genetic and biochemical studies as well as deep sequencing analyses, we find that AGO mutations disrupting miRNA 3' binding are sufficient to trigger extensive miRNA 3’ modifications in HEK293T cells and in cancer patients. Comparing these modifications in TUT4, TUT7 and DIS3L2 knockout cells, we find that TUT7 is more robust than TUT4 in oligo-uridylating mature miRNAs, which in turn leads to their degradation by the DIS3L2 exonuclease. Our findings indicate a decay machinery removing AGO-associated miRNAs with an exposed 3' end. A set of endogenous miRNAs including miR-7 are targeted by this machinery presumably due to target-directed miRNA degradation.
Project description:The exosome-independent exoribonuclease DIS3L2 is mutated in Perlman syndrome. Here we used extensive global transcriptomic and targeted biochemical analyses to identify novel DIS3L2 substrates in human cells. We show that DIS3L2 regulates pol II transcripts, comprising selected canonical and histone-coding mRNAs, and a novel FTL_short RNA from the ferritin mRNA 5' UTR. Importantly, DIS3L2 contributes to surveillance of pre-snRNAs during their cytoplasmic maturation. Among pol III transcripts, DIS3L2 particularly targets vault and Y RNAs and an Alu-like element BC200 RNA, but not Alu repeats, which are removed by exosome-associated DIS3. Using 3' RACE-Seq, we demonstrate that all novel DIS3L2 substrates are uridylated in vivo by TUT4/TUT7 poly(U) polymerases. Uridylation-dependent DIS3L2-mediated decay can be recapitulated in vitro, thus reinforcing the tight cooperation between DIS3L2 and TUTases. Together these results indicate that catalytically inactive DIS3L2, characteristic of Perlman syndrome, can lead to deregulation of its target RNAs to disturb transcriptome homeostasis.
Project description:The exosome-independent exoribonuclease DIS3L2 is mutated in Perlman syndrome. Here we used extensive global transcriptomic and targeted biochemical analyses to identify novel DIS3L2 substrates in human cells. We show that DIS3L2 regulates pol II transcripts, comprising selected canonical and histone-coding mRNAs, and a novel FTL_short RNA from the ferritin mRNA 5' UTR. Importantly, DIS3L2 contributes to surveillance of pre-snRNAs during their cytoplasmic maturation. Among pol III transcripts, DIS3L2 particularly targets vault and Y RNAs and an Alu-like element BC200 RNA, but not Alu repeats, which are removed by exosome-associated DIS3. Using 3' RACE-Seq, we demonstrate that all novel DIS3L2 substrates are uridylated in vivo by TUT4/TUT7 poly(U) polymerases. Uridylation-dependent DIS3L2-mediated decay can be recapitulated in vitro, thus reinforcing the tight cooperation between DIS3L2 and TUTases. Together these results indicate that catalytically inactive DIS3L2, characteristic of Perlman syndrome, can lead to deregulation of its target RNAs to disturb transcriptome homeostasis. To investigate DIS3L2 functions genome-wide, total RNA samples were collected from model cell lines producing either WT or mut DIS3L2 three days after induction with doxycycline. The RNA samples were rRNA-depleted before preparation of strand-specific total RNA libraries according to the standard TruSeq (Illumina) protocol. TruSeq library preparation favours RNA molecules longer than 200 nt, and shorter transcripts are suboptimal for sequencing via this protocol. Thus, to obtain information about potential DIS3L2 RNA substrates with lengths between 20 and 220 nt, another RNA-Seq was carried out in parallel (with size selection through gel purification). The stable inducible HEK293 cell lines producing DIS3L2 variants were obtained using âpAL_01â and âpAL_02â plasmid constructs and the Flp-In⢠T-REx⢠system according to the manufacturerâs guidelines. âpAL_01â and âpAL_02â plasmids are vectors for co-expression of recoded C-terminal FLAG-tagged DIS3L2 [wild type (WT) variant or its catalytic mutant counterpart (mut), respectively] and sh-miRNAs directed against endogenous DIS3L2 mRNA.
Project description:Terminal uridylation of mRNAs poly(A) tails by Terminal Uridylyl Transferases (TUTs) promote transcript decay. Here, we investigate the role of two functionally redundant mammalian TUTs, TUT4 and TUT7 (TUT4/7), in mouse hepatitis virus (MHV) RNA processing. We generated a TUT4/7 knock-down 17-CL1 cell line using lentivirus encoding shRNAs against Tut4 and Tut7 transcripts (shTUT4/7) and a control 17-CL1 cell line (shCTL) with a non-targeting shRNA. We then infected the shCTL and shTUT4/7 cells with MHV and isolated RNA at 24- and 48-hours post-infection (hpi). We found that viral RNA poly(A) tails of about 20 and 40 nucleotides are highly uridylated and that the uridylation of the 20 nucleotide long tails is dependent on TUT4/7. Depletion of TUT4/7 also resulted in an accumulation of the viral RNA.
Project description:To study the impact of TUT4 and TUT7 on miRNA and piRNA biology, Tut4 and Tut7 were conditionally deleted in differentiating spermatogonia. Total RNA samples from TUT4 and TUT7-deficient pachytene-diplotene cells were used to generate small RNAs libraries.
Project description:Rapid and widespread mRNA decay is a previously unappreciated feature of apoptosis. Previous work showed that apoptotic mRNA decay depends on mitochondrial outer membrane permeabilization (MOMP) and the RNA-processing enzymes, TUT4, TUT7, and DIS3L2. Which RNAs are decayed, however, was not known. Here we present RNA-seq data of TRAIL-induced apoptosis in HCT116 cells showing global decay of mRNAs as well as polyadenylated noncoding RNAs, beginning at the 3’-end.
Project description:To study the roles of the proteins TUT4, TUT7 and UPF2 in spermatogenesis, their genes were conditionally deleted in differentiating spermatogonia. Total RNA samples from TUT4 and TUT7-deficient or UPF2-deficient pachytene/diplotene cells were subjected to array profiling.
Project description:To study the impact of the proteins TUT4 and TUT7 on the transcriptome their genes were conditionally deleted in GV oocytes, MEFs, ECSs, liver and Bone marrow. Total RNA samples from the TUT4 and TUT7 deficient tissues/cells (together with their control tissues/cells) were subjected to array profiling.
Project description:To study the impact of the proteins TUT4 and TUT7 on the miRNome, their genes were conditionally deleted in MEFs, ESCs, liver and bone marrow. Total RNA samples from the TUT4 and TUT7 deficient tissues/cells (together with their control tissues/cells) were used to generate microRNA libraries.
Project description:Terminal uridylyl transferases (TUTs) function as integral regulators of microRNA (miRNA) biogenesis by modifying the end structure of precursor miRNA (pre-miRNA). Using biochemistry and deep sequencing techniques, we here investigate the mechanism how human TUT7 recognizes and uridylates pre-miRNAs. We show that the overhang of a pre-miRNA is the key structural element that TUT7 and its paralogues, TUT4 and TUT2, recognize. For group II pre-miRNAs which have a 1 nt 3’ overhang, TUT7 restores the canonical end structure (2 nt 3’ overhang) by mono-uridylation, and thereby promotes miRNA biogenesis. Interestingly, once the 3’ end is receded into the stem (3’ trimmed pre-miRNAs such as Ago-cleaved-pre-miRNA), TUT7 effectively generates an oligo-U tail that consequently leads to degradation. Our single-molecule study further suggests that a distributive mode is employed for both pathways, but the overhang length determines the frequency of TUT7-RNA interaction. Our results explain how TUT7 and TUT4 differentiate pre-miRNA species and reveal a role for TUT7 and TUT4 in the oligo-uridylation and removal of defective pre-miRNAs.