Project description:We collected samples of Pistil, Plain Valve, Plain lip and Plain calyx from the same period and quenched them in liquid nitrogen. Two biological replications were performed in each sample. TMT labeled quantitative proteomics was used to analyze different proteins in different tissues. GO and KEGG were used to analyze the differentially expressed proteins in different tissues, and the key proteins in the important pathway were found
Project description:Abstract - 18S nonfunctional rRNA decay (NRD) detects and eliminates translationally nonfunctional 18S rRNA. While this process is critical for ribosome quality control, the mechanisms underlying nonfunctional 18S rRNA turnover remain elusive, particularly in mammals. Here, we show that mammalian 18S NRD initiates through the integrated stress response (ISR) via GCN2. Nonfunctional 18S rRNA induces translational arrest at start sites. Biochemical analyses demonstrate that ISR activation limits translation initiation and attenuates collisions between scanning 43S preinitiation complexes and stalled nonfunctional ribosomes. The ISR promotes 18S NRD and 40S ribosomal protein turnover by RNF10-mediated ubiquitination. Ultimately, RIOK3 binds the resulting ubiquitinated 40S subunits and facilitates 18S rRNA decay. Overall, mammalian 18S NRD acts through GCN2, followed by ubiquitin-dependent 18S rRNA degradation involving the ubiquitin E3 ligase RNF10 and the atypical protein kinase RIOK3. These findings establish a dynamic feedback mechanism by which the GCN2-RNF10-RIOK3 axis surveils ribosome functionality at the translation initiation step.
Project description:Ribosome biogenesis is essential for protein synthesis in gene expression. Yeast eIF5B has been shown biochemically to facilitate 18S rRNA 3’ end maturation during late-40S ribosomal subunit assembly and gate the transition from translation initiation to elongation. But the effects of eIF5B have not been studied at the genome-wide level in any organism, and 18S rRNA 3’ end maturation is poorly understood in plants. Arabidopsis HOT3/eIF5B1 was found to promote development and heat-stress acclimation by translational regulation, but its molecular function remained unknown. Here, we show that HOT3 is a late-stage ribosome biogenesis factor that facilitates 18S rRNA 3’ end processing and is a translation initiation factor that globally impacts the transition from initiation to elongation. By developing and implementing 18S-ENDseq, we revealed previously unknown events in 18S rRNA 3’ end maturation or metabolism. We quantitatively defined new processing hotspots and identified adenylation as the prevalent non-templated RNA modification at the 3’ ends of pre-18S rRNAs. Aberrant 18S rRNA maturation in hot3 further activated RNAi to generate RDR1- and DCL2/4-dependent risiRNAs mainly from a 3’ portion of 18S rRNA. We further showed that risiRNAs in hot3 were predominantly localized in ribosome-free fractions not responsible for the 18S rRNA maturation or translation initiation defects in hot3. Our study uncovered the molecular function of HOT3/eIF5B1 in 18S rRNA maturation at the late-40S assembly stage and revealed the regulatory crosstalk among ribosome biogenesis, mRNA translation initiation, and siRNA biogenesis in plants.
Project description:Human papilloma virus (HPV)-driven cutaneous squamous cell carcinoma (cSCC) is the most common cancer in immunosuppressed patients. Despite indications suggesting that HPV promotes genomic instability during cSCC development, the molecular pathways underpinning HPV-driven cSCC development remain unknown. We compared the transcriptome of HPV-driven mouse cSCC with normal skin and observed higher amounts of transcripts for Porcupine and WNT ligands in cSCC, suggesting a role for WNT-signaling in cSCC progression. We confirmed increased Porcupine expression in human cSCC samples. Blocking the secretion of WNT-ligands by the Porcupine inhibitor LGK974 significantly diminished initiation and progression of HPV-driven cSCC. Administration of LGK974 to mice with established cSCC resulted in differentiation of cancer cells and significant reduction of the cancer stem cell compartment. Thus, WNT/b-catenin signaling is essential for HPV-driven cSCC initiation and progression as well as for maintaining the cancer stem cell niche. Interference with WNT-secretion may thus represent a promising approach for therapeutic intervention.
Project description:RNA sequencing with differential gene expression analysis was performed on AsPC-1 pancreatic ductal adenocarcinoma (PDAC) cells at multiple time points with a Porcupine inhibitor (LGK974) to identify mechanisms underpinning transcriptional effects.
Project description:The secretion of mammalian Wnt Ligands within the cell is dependent on the activity of Porcupine, a gene located on the X chromosome that encodes for a membrane bound o-acyl transferase. Porcupine-dependent Wnt signalling was previously shown to be essential for the post-natal maintenance of endometrial glands, structures that are essential for implantation and fertility. Previous data has implicated the multiple members of the Wnt family expressed in the female uterus to be involved in a coordinated crosstalk between the luminal and stromal compartments of the uterus, ensuring the proper development of the uterus and successful fertility. We have generated a conditional mutant of Porcupine in the luminal epithelium (cKOepi) of the uterus, thus eliminating Wnt7a/b and Wnt11, to address the nature of this crosstalk. Unlike global luminal-stromal mutants, post-natal ablation of Porcupine in the luminal epithelium alone does not affect the maintenance of the endometrial glands in adults. Uterine glands are still visible in the adult cKOepi, albeit in a smaller number than that of control uteri. Despite having uterine glands, cKOepi females remain completely infertile. We have attributed the sterility of these females to be in part due to defects in implantation and decidualization; cKOepi fail to respond to decidual induction by artificial means. Interestingly, progesterone supplementation rescues the observed implantation defects, although observed decidual soon seem to become resorptive. Microarray analysis of cKOepi during implantation has reveals several potential targets for luminal WNT that may be responsible for the observed phenotype including: Lef1, Hoxa10, Wnt4, Wnt16 Notch1, Notch4 and Dll4 .
Project description:Ribosome biogenesis is essential for protein synthesis in gene expression. Yeast eIF5B has been shown biochemically to facilitate 18S rRNA 3’ end maturation during late-40S ribosomal subunit assembly and gate the transition from translation initiation to elongation. But the effects of eIF5B have not been studied at the genome-wide level in any organism, and 18S rRNA 3’ end maturation is poorly understood in plants. Arabidopsis HOT3/eIF5B1 was found to promote development and heat-stress acclimation by translational regulation, but its molecular function remained unknown. Here, we show that HOT3 is a late-stage ribosome biogenesis factor that facilitates 18S rRNA 3’ end processing and is a translation initiation factor that globally impacts the transition from initiation to elongation. By developing and implementing 18S-ENDseq, we revealed previously unknown events in 18S rRNA 3’ end maturation or metabolism. We quantitatively defined new processing hotspots and identified adenylation as the prevalent non-templated RNA modification at the 3’ ends of pre-18S rRNAs. Aberrant 18S rRNA maturation in hot3 further activated RNAi to generate RDR1- and DCL2/4-dependent risiRNAs mainly from a 3’ portion of 18S rRNA. We further showed that risiRNAs in hot3 were predominantly localized in ribosome-free fractions not responsible for the 18S rRNA maturation or translation initiation defects in hot3. Our study uncovered the molecular function of HOT3/eIF5B1 in 18S rRNA maturation at the late-40S assembly stage and revealed the regulatory crosstalk among ribosome biogenesis, mRNA translation initiation, and siRNA biogenesis in plants.