Molecular and genetic analysis of novel Slicer-dependent miRNA pathways in blood Most conserved microRNAs (miRNAs) are generated by a biogenesis pathway that deposits them into an Argonaute effector, guiding them to broad regulatory target networks. Amongst the cohort of four mammalian Argonautes, only Ago2 has catalytic ability to cleave transcripts, an enzymatic activity known as Slicing that underlies experimental RNA interference. Nevertheless, the endogenous biological usage of mammalian Slicing remains largely mysterious. Our previous and ongoing studies provide the unexpected perspective of multiple Slicing-dependent biogenesis strategies that generate both Dicer-independent and Dicer-dependent erythroid miRNAs. These data strongly support our hypothesis that a dominant usage of Ago2 catalysis is to generate specific conserved miRNAs in the blood system. Our extensive preliminary data are the basis of (1) a series of biochemical and genomic experiments to elucidate a novel Slicing-dependent miRNA biogenesis mechanism, (2) genetic studies of novel knockout animals of erythroid, Slicing-dependent miRNAs in normal development, blood homeostasis and leukemia, and (3) molecular genetic analyses that seek to connect dysregulated processes in Ago2-catalytically defective blood system to specific Slicing- dependent miRNAs. These studies will bring new insights on post-transcriptional control of erythroid development, homeostasis, and blood cancer, as well as pinpoint the functional basis of mammalian RNAi to the generation of erythroid-specific miRNAs.

Public Health Relevance

microRNAs (miRNAs) are ~22 nucleotide RNA molecules that guide Argonaute (Ago) effector complexes to target transcripts for repression. Collectively, miRNAs mediate broad gene regulatory networks with substantial impact on disease and cancer. Special Ago proteins, such as mammalian Ago2, have the ability to cleave target transcripts. This enzymatic activity, referred to as 'Slicing', underlies the powerful experimental tecnique of RNA interference, but the endogenous biological significance of Slicing is poorly understood. Our previous and ongoing studies demonstrate that in mammals, Slicing activity is intimately and fundamentally tied to the erythroid system. In particular, we show that there are multiple non-canonical biogenesis mechanisms for erythroid-restricted miRNAs that uniquely require Ago2-Slicing activity. We propose a combination of biochemical, molecular, genetic, and genomewide studies to elucidate the biological requirements of non-canonical erythroid miRNAs, and how they surprisingly underlie the blood defects of Slicing-defective mammals.

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Research Project (R01)
Project #
5R01HL135564-04
Application #
9846225
Study Section
Molecular and Cellular Hematology Study Section (MCH)
Program Officer
Bai, C Brian
Project Start
2017-04-10
Project End
2021-01-31
Budget Start
2020-02-01
Budget End
2021-01-31
Support Year
4
Fiscal Year
2020
Total Cost
Indirect Cost
Name
Sloan-Kettering Institute for Cancer Research
Department
Type
DUNS #
064931884
City
New York
State
NY
Country
United States
Zip Code
10065
Teijeiro, Virginia; Yang, Dapeng; Majumdar, Sonali et al. (2018) DICER1 Is Essential for Self-Renewal of Human Embryonic Stem Cells. Stem Cell Reports 11:616-625
Jee, David; Yang, Jr-Shiuan; Park, Sun-Mi et al. (2018) Dual Strategies for Argonaute2-Mediated Biogenesis of Erythroid miRNAs Underlie Conserved Requirements for Slicing in Mammals. Mol Cell 69:265-278.e6
Bhagat, Tushar D; Chen, Si; Bartenstein, Matthias et al. (2017) Epigenetically Aberrant Stroma in MDS Propagates Disease via Wnt/?-Catenin Activation. Cancer Res 77:4846-4857
Vu, Ly P; Prieto, Camila; Amin, Elianna M et al. (2017) Functional screen of MSI2 interactors identifies an essential role for SYNCRIP in myeloid leukemia stem cells. Nat Genet 49:866-875