Project description:N6-methyladenosine (m6A) is the most prevalent internal modification of messenger RNA (mRNA) in higher eukaryotes. Here we report ALKBH5 as a new mammalian demethylase that oxidatively removes the m6A modification in mRNA in vitro and inside cells. This demethylation activity of ALKBH5 significantly affects mRNA export and RNA metabolism as well as the assembly of mRNA processing factors in nuclear speckles. Alkbh5-deficient male mice are characterized by impaired fertility resulting from apoptosis that affects meiotic metaphase-stage spermatocytes. In accordance with this defect, we have identified in mouse testes 1552 differentially expressed genes which cover broad functional categories and include spermatogenesis-related mRNAs involved in the p53 functional interaction network. We show that Alkbh5-deficiency impacts the expression levels of some of these mRNAs, supporting the observed phenotype. The discovery of this new RNA demethylase strongly suggests that the reversible m6A modification plays fundamental and broad functions in mammalian cells. RNA-seq in two cell types
Project description:Since m6A demethylases (FTO and ALKBH5) have been reported to be involved in pre-mRNA splicing regulation, we hypothesized that dynamic m6A distribution during mRNA maturation might involve removal of m6A in internal exons by FTO or ALKBH5 accompanied by splicing factors. To explore this we performed pull-down assays coupled with protein mass spectrometry.
Project description:N6-methyladenonsine (m6A) modification locates ubiquitously in mammalian mRNA, and profoundly impacts various physiological processes and pathogenesis. However, the precise involvement of m6A in early endoderm development has yet to be fully elucidated. Here, we reported that depletion of the m6A demethylase ALKBH5 in human embryonic stem cells (hESCs) severely impaired definitive endoderm (DE) differentiation. Within this process, ALKBH5-/- hESCs failed to undergo the primitive streak (PS) intermediate transition, which is considered as a prelude to endoderm specification. Mechanistically, we demonstrated that ALKBH5 deficiency induced m6A hypermethylation around the 3’ untranslated region (3’UTR) of GATA6 transcripts and destabilized GATA6 mRNA in a YTHDF2-dependent manner. Moreover, dysregulation of GATA6 expression ablated its occupancy with critical regulators of Wnt/β-catenin signaling pathway, thereby disrupting the signaling logic underlying DE formation. Overall, our findings unveil a mechanism whereby the ALKBH5-GATA6-WNT/β-catenin axis modulates human in vitro DE induction, and present novel insights on m6A modification in early embryonic development.
Project description:ALKBH5 play important role in regulation of trophoblast invasion, we examined the downstream genes of ALKBH5 via transcriptome sequencing
Project description:ALKBH5 is the RNA N(6)-methyladenosine (m6A) demethylase. To understhand the function and mechnism of ALKBH5 in human acute myeloid leukemia, we compared the translational efficiency in wild-type and ALKBH5-knock-down MOLM-13 cells.
Project description:We here report ALKBH5, a m6A RNA demethylase, as a crucial oncogene in multiple myeloma (MM). Using various MM models, we demonstrated a critical requirement of ALKBH5 for MM cell proliferation in vitro and in vivo. To identify the potential mRNA targets of ALKBH5, we conducted m6A-seq with mRNA samples enriched from MM cells with or without ALKBH5 knockdown.
Project description:N6-methyladenosine (m6A) is the most printed and prevalent mRNA modification, which was verified to be closely correlated with cancer occurrence and progression. As m6A demethlyase, the dysregulation of ALKBH5 was observed in various cancer. However, the role and underlying machinery of ALKBH5 in NSCLC pathogenesis, especially the chemo-resistance was poorly elucidated. The current study indicated that ALKBH5 was decreased during paclitaxel (PTX) resistant process and its down-regulation usually implied poor prognosis of NSCLC patients. Over-expression of ALKBH5 in PTX-resistant cells could suppressed cell proliferation and enhanced chemo-sensitivity. Whereas, knockdown of ALKBH5 exerted opposite effect, which further supported the tumor suppressive role of ALKBH5. Over-expression of ALKBH5 also could reverse the EMT process in PTX-resistant cancer cells. Mechanistically, data of RNA-seq, Real-time PCR and western blotting indicted that CEMIP, also known as KIAA1199, may be the downstream target of ALKBH5. And ALKBH5 could negatively regulated the CEMIP level by decreasing its mRNA stability. Collectively, current data demonstrated that ALKBH5/CEMIP axis modulates the EMT process in NSCLC, which in turn regulates chemo-sensitivity of cancer cells to PTX.
Project description:To identify the potential mRNA targets of ALKBH5, we conducted RNA-seq of mRNA samples enriched from AML cells with ALKBH5 knockdown
Project description:We performed the transcripome-wild m6A-sequencing to compare the m6A profiles of negative control (NC) HeLa cells and ALKBH5 KO HeLa cells stably re-expressing wild type ALKBH5 (WT) or its mutant K235R (K235R)