Project description:Uridylation occurs pervasively on mRNAs, yet its mechanism and significance remain unknown. By applying TAIL-seq, we identify TUT4 and TUT7 (TUT4/7), also known as ZCCHC11 and ZCCHC6, respectively, as mRNA uridylation enzymes. Uridylation readily occurs on deadenylated mRNAs in cells. Consistently, purified TUT4/7 selectively recognize and uridylate RNAs with short A-tails (less than ∼ 25 nt) in vitro. PABPC1 antagonizes uridylation of polyadenylated mRNAs, contributing to the specificity for short A-tails. In cells depleted of TUT4/7, the vast majority of mRNAs lose the oligo-U-tails, and their half-lives are extended. Suppression of mRNA decay factors leads to the accumulation of oligo-uridylated mRNAs. In line with this, microRNA induces uridylation of its targets, and TUT4/7 are required for enhanced decay of microRNA targets. Our study explains the mechanism underlying selective uridylation of deadenylated mRNAs and demonstrates a fundamental role of oligo-U-tail as a molecular mark for global mRNA decay.
Project description:Uridylation occurs pervasively on mRNAs in mammals, yet its mechanism and significance remain unknown. Here we identify TUT4 and TUT7 (also known as ZCCHC11 and ZCCHC6, respectively) as the enzymes that uridylate mRNAs. Uridylation readily occurs on deadenylated mRNAs that are not associated with poly(A) binding protein (PABPC1) in cells. Consistently, purified TUT4 and TUT7 (TUT4/7) selectively uridylate RNAs with short A tails (< ~25 nt) while PABPC1 antagonizes uridylation of polyadenylated mRNAs in vitro. In cells depleted of TUT4/7, the vast majority of mRNAs lose the U tails, and their half-lives are extended. Suppression of mRNA decay factors leads to the accumulation of uridylated mRNAs. In line with this, microRNA induces uridylation of its targets, and TUT4/7 is required for enhanced decay of microRNA targets. Our study explains the mechanism underlying selective uridylation of deadenylated mRNAs, and demonstrates a fundamental role of the U tail as a molecular mark for global mRNA decay.
Project description:Uridylation occurs pervasively on mRNAs in mammals, yet its mechanism and significance remain unknown. Here we identify TUT4 and TUT7 (also known as ZCCHC11 and ZCCHC6, respectively) as the enzymes that uridylate mRNAs. Uridylation readily occurs on deadenylated mRNAs that are not associated with poly(A) binding protein (PABPC1) in cells. Consistently, purified TUT4 and TUT7 (TUT4/7) selectively uridylate RNAs with short A tails (< ~25 nt) while PABPC1 antagonizes uridylation of polyadenylated mRNAs in vitro. In cells depleted of TUT4/7, the vast majority of mRNAs lose the U tails, and their half-lives are extended. Suppression of mRNA decay factors leads to the accumulation of uridylated mRNAs. In line with this, microRNA induces uridylation of its targets, and TUT4/7 is required for enhanced decay of microRNA targets. Our study explains the mechanism underlying selective uridylation of deadenylated mRNAs, and demonstrates a fundamental role of the U tail as a molecular mark for global mRNA decay.
Project description:Uridylation occurs pervasively on mRNAs in mammals, yet its mechanism and significance remain unknown. Here we identify TUT4 and TUT7 (also known as ZCCHC11 and ZCCHC6, respectively) as the enzymes that uridylate mRNAs. Uridylation readily occurs on deadenylated mRNAs that are not associated with poly(A) binding protein (PABPC1) in cells. Consistently, purified TUT4 and TUT7 (TUT4/7) selectively uridylate RNAs with short A tails (< ~25 nt) while PABPC1 antagonizes uridylation of polyadenylated mRNAs in vitro. In cells depleted of TUT4/7, the vast majority of mRNAs lose the U tails, and their half-lives are extended. Suppression of mRNA decay factors leads to the accumulation of uridylated mRNAs. In line with this, microRNA induces uridylation of its targets, and TUT4/7 is required for enhanced decay of microRNA targets. Our study explains the mechanism underlying selective uridylation of deadenylated mRNAs, and demonstrates a fundamental role of the U tail as a molecular mark for global mRNA decay. HeLa cells were knocked down of control or TUT4/7, then total RNAs were prepared for RNA-seq on 0, 1, 2, 4h after actinomycin D treatment. The whole processes of experiments were repeated two times.
Project description:Uridylation occurs pervasively on mRNAs in mammals, yet its mechanism and significance remain unknown. Here we identify TUT4 and TUT7 (also known as ZCCHC11 and ZCCHC6, respectively) as the enzymes that uridylate mRNAs. Uridylation readily occurs on deadenylated mRNAs that are not associated with poly(A) binding protein (PABPC1) in cells. Consistently, purified TUT4 and TUT7 (TUT4/7) selectively uridylate RNAs with short A tails (< ~25 nt) while PABPC1 antagonizes uridylation of polyadenylated mRNAs in vitro. In cells depleted of TUT4/7, the vast majority of mRNAs lose the U tails, and their half-lives are extended. Suppression of mRNA decay factors leads to the accumulation of uridylated mRNAs. In line with this, microRNA induces uridylation of its targets, and TUT4/7 is required for enhanced decay of microRNA targets. Our study explains the mechanism underlying selective uridylation of deadenylated mRNAs, and demonstrates a fundamental role of the U tail as a molecular mark for global mRNA decay. Thirteen separate sets of TAIL-seq experiments were performed. Each set includes a negative control for transfection, immunoprecipitation, or knockout cell generation. Experimental samples were treated with various conditions including siRNA transfection, transdominant negative protein expression, TALEN-based gene knockout, or immunoprecipitation. The 'README-TAIL-seq.txt' include detailed information about structure of seq entries in FASTQ files and of processed data for 3' end modifications.
Project description:Recent small RNA sequencing data has uncovered 3' end modification of mature microRNAs (miRNAs). This non-templated nucleotide addition can impact miRNA gene regulatory networks through the control of miRNA stability or by interfering with the repression of target mRNAs. The miRNA modifying enzymes responsible for this regulation remain largely uncharacterized. Here we describe the ability for two related terminal uridyl transferases (TUTases), Zcchc6 (TUT7) and Zcchc11 (TUT4), to 3' mono-uridylate a specific subset of miRNAs involved in cell differentiation and Homeobox (Hox) gene control. Zcchc6/11 selectively uridylates these miRNAs in vitro, and we biochemically define a bipartite sequence motif that is necessary and sufficient to confer Zcchc6/11 catalyzed uridylation. Depletion of these TUTases in cultured cells causes the selective loss of 3' mono-uridylation of many of the same miRNAs. Upon TUTase-dependent loss of uridylation, we observe a concomitant increase in non-templated 3' mono-adenylation. Furthermore, TUTase inhibition in Zebrafish embryos causes developmental defects and aberrant Hox expression. Our results uncover the molecular basis for selective miRNA mono-uridylation by Zcchc6/11, highlight the precise control of different 3' miRNA modifications in cells and have implications for miRNA and Hox gene regulation during development.
Project description:The replication-dependent histone mRNAs end in a stem-loop instead of the poly(A) tail present at the 3' end of all other cellular mRNAs. Following processing, the 3' end of histone mRNAs is trimmed to 3 nucleotides (nt) after the stem-loop, and this length is maintained by addition of nontemplated uridines if the mRNA is further trimmed by 3'hExo. These mRNAs are tightly cell-cycle regulated, and a critical regulatory step is rapid degradation of the histone mRNAs when DNA replication is inhibited. An initial step in histone mRNA degradation is digestion 2-4 nt into the stem by 3'hExo and uridylation of this intermediate. The mRNA is then subsequently degraded by the exosome, with stalled intermediates being uridylated. The enzyme(s) responsible for oligouridylation of histone mRNAs have not been definitively identified. Using high-throughput sequencing of histone mRNAs and degradation intermediates, we find that knockdown of TUT7 reduces both the uridylation at the 3' end as well as uridylation of the major degradation intermediate in the stem. In contrast, knockdown of TUT4 did not alter the uridylation pattern at the 3' end and had a small effect on uridylation in the stem-loop during histone mRNA degradation. Knockdown of 3'hExo also altered the uridylation of histone mRNAs, suggesting that TUT7 and 3'hExo function together in trimming and uridylating histone mRNAs.