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CRISPR screening identifies M1AP as a new MYC regulator with a promoter-reporter system

BACKGROUND: MYC is one of the proto-oncogenes contributing to tumorigenesis in many human cancers. Although the mechanism of MYC regulation is still not fully understood, learning about the comprehensive mechanism controlling the transcriptional activity of MYC will lead to therapeutic targets. The...

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Autores principales: Yamamoto, Akiko, Kurata, Morito, Onishi, Iichiroh, Sugita, Keisuke, Matsumura, Miwa, Ishibashi, Sachiko, Ikeda, Masumi, Yamamoto, Kouhei, Kitagawa, Masanobu
Formato: Online Artículo Texto
Lenguaje:English
Publicado: PeerJ Inc. 2020
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7210806/
https://www.ncbi.nlm.nih.gov/pubmed/32411526
http://dx.doi.org/10.7717/peerj.9046
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author Yamamoto, Akiko
Kurata, Morito
Onishi, Iichiroh
Sugita, Keisuke
Matsumura, Miwa
Ishibashi, Sachiko
Ikeda, Masumi
Yamamoto, Kouhei
Kitagawa, Masanobu
author_facet Yamamoto, Akiko
Kurata, Morito
Onishi, Iichiroh
Sugita, Keisuke
Matsumura, Miwa
Ishibashi, Sachiko
Ikeda, Masumi
Yamamoto, Kouhei
Kitagawa, Masanobu
author_sort Yamamoto, Akiko
collection PubMed
description BACKGROUND: MYC is one of the proto-oncogenes contributing to tumorigenesis in many human cancers. Although the mechanism of MYC regulation is still not fully understood, learning about the comprehensive mechanism controlling the transcriptional activity of MYC will lead to therapeutic targets. The CRISPR/Cas9 library system is a simple and powerful screening technique. This study aims to identify new transcriptional upstream activators of MYC using the CRISPR activation library with new promoter-reporter systems. METHODS AND RESULTS: The MYC promoter-reporter system was developed with a photoconvertible fluorescent protein, Dendra2, and named “pMYC-promoter-Dendra2.” This MYC promoter-reporter system was designed to harbor a proximal MYC promoter at (3.1 kb). Both the CRISPR activation library and pMYC-promoter-Dendra2 were induced to HEK 293T cells, and Dendra2-positive cells, that are supposed that MYC should be upregulated, were collected individually by a cell sorter. Among the 169 cells collected, 12 clones were successfully established. Then, pMYC-promoter-Dendra2 was transfected again into these 12 clones, and two of 12 clones showed Dendra2 positivity. In this procedure, the cells with non-specific autofluorescence were correctly distinguished by utilizing the photoswitchable character of Dendra2. Using extracted genomic DNA of these two Dendra2 positive clones, polymerase chain reaction (PCR) was performed to amplify the guide RNA (gRNA) containing region, which was introduced by the CRISPR activation library. Eventually, PLEKHO2, MICU, MBTPS1, and M1AP were identified, and these gRNAs were transfected individually into HEK 293T cells again using the CRISPR activation system. Only M1AP gRNA transfected cells showed Dendra2-positive fluorescence. Then, the overexpression vector for M1AP with a doxycycline-inducible vector confirmed that M1AP induced high MYC expression by real-time quantitative PCR and western blot. Furthermore, the dual-luciferase assay showed a significant increase of promoter activity, and MYC mRNA was higher in M1AP- overexpressing cells. M1AP is highly expressed in several cancers, though, a positive correlation between M1AP and MYC was observed only in human acute myeloid leukemia. CONCLUSION: The present study confirmed that the experimental method using the CRISPR library technology functions effectively for the identification of molecules that activate endogenous MYC. This method will help elucidate the regulatory mechanism of MYC expression, as well as supporting further drug research against malignant tumors.
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spelling pubmed-72108062020-05-14 CRISPR screening identifies M1AP as a new MYC regulator with a promoter-reporter system Yamamoto, Akiko Kurata, Morito Onishi, Iichiroh Sugita, Keisuke Matsumura, Miwa Ishibashi, Sachiko Ikeda, Masumi Yamamoto, Kouhei Kitagawa, Masanobu PeerJ Cell Biology BACKGROUND: MYC is one of the proto-oncogenes contributing to tumorigenesis in many human cancers. Although the mechanism of MYC regulation is still not fully understood, learning about the comprehensive mechanism controlling the transcriptional activity of MYC will lead to therapeutic targets. The CRISPR/Cas9 library system is a simple and powerful screening technique. This study aims to identify new transcriptional upstream activators of MYC using the CRISPR activation library with new promoter-reporter systems. METHODS AND RESULTS: The MYC promoter-reporter system was developed with a photoconvertible fluorescent protein, Dendra2, and named “pMYC-promoter-Dendra2.” This MYC promoter-reporter system was designed to harbor a proximal MYC promoter at (3.1 kb). Both the CRISPR activation library and pMYC-promoter-Dendra2 were induced to HEK 293T cells, and Dendra2-positive cells, that are supposed that MYC should be upregulated, were collected individually by a cell sorter. Among the 169 cells collected, 12 clones were successfully established. Then, pMYC-promoter-Dendra2 was transfected again into these 12 clones, and two of 12 clones showed Dendra2 positivity. In this procedure, the cells with non-specific autofluorescence were correctly distinguished by utilizing the photoswitchable character of Dendra2. Using extracted genomic DNA of these two Dendra2 positive clones, polymerase chain reaction (PCR) was performed to amplify the guide RNA (gRNA) containing region, which was introduced by the CRISPR activation library. Eventually, PLEKHO2, MICU, MBTPS1, and M1AP were identified, and these gRNAs were transfected individually into HEK 293T cells again using the CRISPR activation system. Only M1AP gRNA transfected cells showed Dendra2-positive fluorescence. Then, the overexpression vector for M1AP with a doxycycline-inducible vector confirmed that M1AP induced high MYC expression by real-time quantitative PCR and western blot. Furthermore, the dual-luciferase assay showed a significant increase of promoter activity, and MYC mRNA was higher in M1AP- overexpressing cells. M1AP is highly expressed in several cancers, though, a positive correlation between M1AP and MYC was observed only in human acute myeloid leukemia. CONCLUSION: The present study confirmed that the experimental method using the CRISPR library technology functions effectively for the identification of molecules that activate endogenous MYC. This method will help elucidate the regulatory mechanism of MYC expression, as well as supporting further drug research against malignant tumors. PeerJ Inc. 2020-05-06 /pmc/articles/PMC7210806/ /pubmed/32411526 http://dx.doi.org/10.7717/peerj.9046 Text en ©2020 Yamamoto et al. https://creativecommons.org/licenses/by/4.0/ This is an open access article distributed under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0/) , which permits unrestricted use, distribution, reproduction and adaptation in any medium and for any purpose provided that it is properly attributed. For attribution, the original author(s), title, publication source (PeerJ) and either DOI or URL of the article must be cited.
spellingShingle Cell Biology
Yamamoto, Akiko
Kurata, Morito
Onishi, Iichiroh
Sugita, Keisuke
Matsumura, Miwa
Ishibashi, Sachiko
Ikeda, Masumi
Yamamoto, Kouhei
Kitagawa, Masanobu
CRISPR screening identifies M1AP as a new MYC regulator with a promoter-reporter system
title CRISPR screening identifies M1AP as a new MYC regulator with a promoter-reporter system
title_full CRISPR screening identifies M1AP as a new MYC regulator with a promoter-reporter system
title_fullStr CRISPR screening identifies M1AP as a new MYC regulator with a promoter-reporter system
title_full_unstemmed CRISPR screening identifies M1AP as a new MYC regulator with a promoter-reporter system
title_short CRISPR screening identifies M1AP as a new MYC regulator with a promoter-reporter system
title_sort crispr screening identifies m1ap as a new myc regulator with a promoter-reporter system
topic Cell Biology
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7210806/
https://www.ncbi.nlm.nih.gov/pubmed/32411526
http://dx.doi.org/10.7717/peerj.9046
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