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Yugami M, Hayakawa-Yano Y, Ogasawara T, Yokoyama K, Furukawa T, Hara H, Hashikami K, Tsuji I, Takebayashi H, Araki S, Okano H, Yano M. Sbp2l contributes to oligodendrocyte maturation through translational control in Tcf7l2 signaling. iScience 2023; 26:108451. [PMID: 38213786 PMCID: PMC10783607 DOI: 10.1016/j.isci.2023.108451] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2023] [Revised: 10/09/2023] [Accepted: 11/10/2023] [Indexed: 01/13/2024] Open
Abstract
Oligodendrocytes (OLs) are the myelin-forming cells in the CNS that support neurons through the insulating sheath of axons. This unique feature and developmental processes are achieved by extrinsic and intrinsic gene expression programs, where RNA-binding proteins can contribute to dynamic and fine-tuned post-transcriptional regulation. Here, we identified SECIS-binding protein 2-like (Sbp2l), which is specifically expressed in OLs by integrated transcriptomics. Histological analysis revealed that Sbp2l is a molecular marker of OL maturation. Sbp2l knockdown (KD) led to suppression of matured OL markers, but not a typical selenoprotein, Gpx4. Transcriptome analysis demonstrated that Sbp2l KD decreased cholesterol-biosynthesis-related genes regulated by Tcf7l2 transcription factor. Indeed, we confirmed the downregulation of Tcf7l2 protein without changing its mRNA in Sbp2l KD OPCs. Furthermore, Sbp2l KO mice showed the decrease of Tcf7l2 protein and deficiency of OL maturation. These results suggest that Sbp2l contributes to OL maturation by translational control of Tcf7l2.
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Affiliation(s)
- Masato Yugami
- Research, Takeda Pharmaceutical Company Limited, 26-1 Muraoka-higashi 2-chome, Fujisawa, Kanagawa 251-8555, Japan
| | - Yoshika Hayakawa-Yano
- Division of Neurobiology and Anatomy, Graduate School of Medical and Dental Sciences, Niigata University, 1-757, Asahimachidori, Chuo-ku, Niigata, Niigata 951-8510, Japan
- Department of Physiology, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582, Japan
| | - Takahisa Ogasawara
- Research, Takeda Pharmaceutical Company Limited, 26-1 Muraoka-higashi 2-chome, Fujisawa, Kanagawa 251-8555, Japan
| | - Kazumasa Yokoyama
- Research, Takeda Pharmaceutical Company Limited, 26-1 Muraoka-higashi 2-chome, Fujisawa, Kanagawa 251-8555, Japan
| | - Takako Furukawa
- Division of Neurobiology and Anatomy, Graduate School of Medical and Dental Sciences, Niigata University, 1-757, Asahimachidori, Chuo-ku, Niigata, Niigata 951-8510, Japan
| | - Hiroe Hara
- Research, Takeda Pharmaceutical Company Limited, 26-1 Muraoka-higashi 2-chome, Fujisawa, Kanagawa 251-8555, Japan
| | - Kentaro Hashikami
- Research, Takeda Pharmaceutical Company Limited, 26-1 Muraoka-higashi 2-chome, Fujisawa, Kanagawa 251-8555, Japan
| | - Isamu Tsuji
- Research, Takeda Pharmaceutical Company Limited, 26-1 Muraoka-higashi 2-chome, Fujisawa, Kanagawa 251-8555, Japan
| | - Hirohide Takebayashi
- Division of Neurobiology and Anatomy, Graduate School of Medical and Dental Sciences, Niigata University, 1-757, Asahimachidori, Chuo-ku, Niigata, Niigata 951-8510, Japan
| | - Shinsuke Araki
- Research, Takeda Pharmaceutical Company Limited, 26-1 Muraoka-higashi 2-chome, Fujisawa, Kanagawa 251-8555, Japan
| | - Hideyuki Okano
- Department of Physiology, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582, Japan
| | - Masato Yano
- Division of Neurobiology and Anatomy, Graduate School of Medical and Dental Sciences, Niigata University, 1-757, Asahimachidori, Chuo-ku, Niigata, Niigata 951-8510, Japan
- Department of Physiology, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582, Japan
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Araki S, Ohori M, Yugami M. Targeting pre-mRNA splicing in cancers: roles, inhibitors, and therapeutic opportunities. Front Oncol 2023; 13:1152087. [PMID: 37342192 PMCID: PMC10277747 DOI: 10.3389/fonc.2023.1152087] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2023] [Accepted: 05/09/2023] [Indexed: 06/22/2023] Open
Abstract
Accumulating evidence has indicated that pre-mRNA splicing plays critical roles in a variety of physiological processes, including development of multiple diseases. In particular, alternative splicing is profoundly involved in cancer progression through abnormal expression or mutation of splicing factors. Small-molecule splicing modulators have recently attracted considerable attention as a novel class of cancer therapeutics, and several splicing modulators are currently being developed for the treatment of patients with various cancers and are in the clinical trial stage. Novel molecular mechanisms modulating alternative splicing have proven to be effective for treating cancer cells resistant to conventional anticancer drugs. Furthermore, molecular mechanism-based combination strategies and patient stratification strategies for cancer treatment targeting pre-mRNA splicing must be considered for cancer therapy in the future. This review summarizes recent progress in the relationship between druggable splicing-related molecules and cancer, highlights small-molecule splicing modulators, and discusses future perspectives of splicing modulation for personalized and combination therapies in cancer treatment.
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Yugami M, Okano H, Nakanishi A, Yano M. Analysis of the nucleocytoplasmic shuttling RNA-binding protein HNRNPU using optimized HITS-CLIP method. PLoS One 2020; 15:e0231450. [PMID: 32302342 PMCID: PMC7164624 DOI: 10.1371/journal.pone.0231450] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2020] [Accepted: 03/24/2020] [Indexed: 01/08/2023] Open
Abstract
RNA-binding proteins (RBPs) control many types of post-transcriptional regulation, including mRNA splicing, mRNA stability, and translational efficiency, by directly binding to their target RNAs and their mutation and dysfunction are often associated with several human neurological diseases and tumorigenesis. Crosslinking immunoprecipitation (CLIP), coupled with high-throughput sequencing (HITS-CLIP), is a powerful technique for investigating the molecular mechanisms underlying disease pathogenesis by comprehensive identification of RBP target sequences at the transcriptome level. However, HITS-CLIP protocol is still required for some optimization due to experimental complication, low efficiency and time-consuming, whose library has to be generated from very small amounts of RNAs. Here we improved a more efficient, rapid, and reproducible CLIP method by optimizing BrdU-CLIP. Our protocol produced a 10-fold greater yield of pre-amplified CLIP library, which resulted in a low duplicate rate of CLIP-tag reads because the number of PCR cycles required for library amplification was reduced. Variance of the yields was also reduced, and the experimental period was shortened by 2 days. Using this, we validated IL-6 expression by a nuclear RBP, HNRNPU, which directly binds the 3’-UTR of IL-6 mRNA in HeLa cells. Importantly, this interaction was only observed in the cytoplasmic fraction, suggesting a role of cytoplasmic HNRNPU in mRNA stability control. This optimized method enables us to accurately identify target genes and provides a snapshot of the protein-RNA interactions of nucleocytoplasmic shuttling RBPs.
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Affiliation(s)
- Masato Yugami
- Takeda Pharmaceutical Company, Ltd, Osaka, Japan
- * E-mail: (MYu); (MYa)
| | - Hideyuki Okano
- Department of Physiology, School of Medicine, Keio University, Minato, Japan
| | | | - Masato Yano
- Department of Physiology, School of Medicine, Keio University, Minato, Japan
- Division of Neurobiology and Anatomy, Graduate School of Medical and Dental Sciences, Niigata University, Niigata, Japan
- * E-mail: (MYu); (MYa)
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Tanoue H, Morinaga J, Yoshizawa T, Yugami M, Itoh H, Nakamura T, Uehara Y, Masuda T, Odagiri H, Sugizaki T, Kadomatsu T, Miyata K, Endo M, Terada K, Ochi H, Takeda S, Yamagata K, Fukuda T, Mizuta H, Oike Y. Angiopoietin-like protein 2 promotes chondrogenic differentiation during bone growth as a cartilage matrix factor. Osteoarthritis Cartilage 2018; 26:108-117. [PMID: 29074299 DOI: 10.1016/j.joca.2017.10.011] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/21/2017] [Revised: 08/30/2017] [Accepted: 10/10/2017] [Indexed: 02/07/2023]
Abstract
OBJECTIVE Chondrocyte differentiation is crucial for long bone growth. Many cartilage extracellular matrix (ECM) proteins reportedly contribute to chondrocyte differentiation, indicating that mechanisms underlying chondrocyte differentiation are likely more complex than previously appreciated. Angiopoietin-like protein 2 (ANGPTL2) is a secreted factor normally abundantly produced in mesenchymal lineage cells such as adipocytes and fibroblasts, but its loss contributes to the pathogenesis of lifestyle- or aging-related diseases. However, the function of ANGPTL2 in chondrocytes, which are also differentiated from mesenchymal stem cells, remains unclear. Here, we investigate whether ANGPTL2 is expressed in or functions in chondrocytes. METHODS First, we evaluated Angptl2 expression during chondrocyte differentiation using chondrogenic ATDC5 cells and wild-type epiphyseal cartilage of newborn mice. We next assessed ANGPTL2 function in chondrogenic differentiation and associated signaling using Angptl2 knockdown ATDC5 cells and Angptl2 knockout mice. RESULTS ANGPTL2 is expressed in chondrocytes, particularly those located in resting and proliferative zones, and accumulates in ECM surrounding chondrocytes. Interestingly, long bone growth was retarded in Angptl2 knockout mice from neonatal to adult stages via attenuation of chondrocyte differentiation. Both in vivo and in vitro experiments show that changes in ANGPTL2 expression can also alter p38 mitogen-activated protein kinase (MAPK) activity mediated by integrin α5β1. CONCLUSION ANGPTL2 contributes to chondrocyte differentiation and subsequent endochondral ossification through α5β1 integrin and p38 MAPK signaling during bone growth. Our findings provide insight into molecular mechanisms governing communication between chondrocytes and surrounding ECM components in bone growth activities.
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Affiliation(s)
- H Tanoue
- Department of Molecular Genetics, Graduate School of Medical Sciences, Kumamoto University, 1-1-1 Honjo,Chuo-ku, Kumamoto 860-8556, Japan; Department of Orthopaedic Surgery, Graduate School of Medical Sciences, Kumamoto University, 1-1-1 Honjo,Chuo-ku, Kumamoto 860-8556, Japan
| | - J Morinaga
- Department of Molecular Genetics, Graduate School of Medical Sciences, Kumamoto University, 1-1-1 Honjo,Chuo-ku, Kumamoto 860-8556, Japan
| | - T Yoshizawa
- Department of Medical Biochemistry, Graduate School of Medical Sciences, Kumamoto University, 1-1-1 Honjo,Chuo-ku, Kumamoto 860-8556, Japan
| | - M Yugami
- Department of Molecular Genetics, Graduate School of Medical Sciences, Kumamoto University, 1-1-1 Honjo,Chuo-ku, Kumamoto 860-8556, Japan; Department of Orthopaedic Surgery, Graduate School of Medical Sciences, Kumamoto University, 1-1-1 Honjo,Chuo-ku, Kumamoto 860-8556, Japan
| | - H Itoh
- Department of Molecular Genetics, Graduate School of Medical Sciences, Kumamoto University, 1-1-1 Honjo,Chuo-ku, Kumamoto 860-8556, Japan; Department of Orthopaedic Surgery, Graduate School of Medical Sciences, Kumamoto University, 1-1-1 Honjo,Chuo-ku, Kumamoto 860-8556, Japan
| | - T Nakamura
- Department of Orthopaedic Surgery, Graduate School of Medical Sciences, Kumamoto University, 1-1-1 Honjo,Chuo-ku, Kumamoto 860-8556, Japan
| | - Y Uehara
- Department of Orthopaedic Surgery, Graduate School of Medical Sciences, Kumamoto University, 1-1-1 Honjo,Chuo-ku, Kumamoto 860-8556, Japan
| | - T Masuda
- Department of Orthopaedic Surgery, Graduate School of Medical Sciences, Kumamoto University, 1-1-1 Honjo,Chuo-ku, Kumamoto 860-8556, Japan
| | - H Odagiri
- Department of Orthopaedic Surgery, Graduate School of Medical Sciences, Kumamoto University, 1-1-1 Honjo,Chuo-ku, Kumamoto 860-8556, Japan
| | - T Sugizaki
- Department of Molecular Genetics, Graduate School of Medical Sciences, Kumamoto University, 1-1-1 Honjo,Chuo-ku, Kumamoto 860-8556, Japan
| | - T Kadomatsu
- Department of Molecular Genetics, Graduate School of Medical Sciences, Kumamoto University, 1-1-1 Honjo,Chuo-ku, Kumamoto 860-8556, Japan
| | - K Miyata
- Department of Molecular Genetics, Graduate School of Medical Sciences, Kumamoto University, 1-1-1 Honjo,Chuo-ku, Kumamoto 860-8556, Japan
| | - M Endo
- Department of Molecular Genetics, Graduate School of Medical Sciences, Kumamoto University, 1-1-1 Honjo,Chuo-ku, Kumamoto 860-8556, Japan
| | - K Terada
- Department of Molecular Genetics, Graduate School of Medical Sciences, Kumamoto University, 1-1-1 Honjo,Chuo-ku, Kumamoto 860-8556, Japan
| | - H Ochi
- Department of Physiology and Cell Biology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8510, Japan
| | - S Takeda
- Endocrine Center, Toranomon Hospital, 2-2-2 Toranomon, Minato-ku, Tokyo, 05-8470, Japan
| | - K Yamagata
- Department of Medical Biochemistry, Graduate School of Medical Sciences, Kumamoto University, 1-1-1 Honjo,Chuo-ku, Kumamoto 860-8556, Japan
| | - T Fukuda
- Department of Anatomy and Neurobiology, Graduate School of Medical Sciences, Kumamoto University, 1-1-1 Honjo,Chuo-ku, Kumamoto 860-8556, Japan
| | - H Mizuta
- Department of Orthopaedic Surgery, Graduate School of Medical Sciences, Kumamoto University, 1-1-1 Honjo,Chuo-ku, Kumamoto 860-8556, Japan
| | - Y Oike
- Department of Molecular Genetics, Graduate School of Medical Sciences, Kumamoto University, 1-1-1 Honjo,Chuo-ku, Kumamoto 860-8556, Japan; Core Research for Evolutional Science and Technology (CREST), Japan Agency for Medical Research and Development (AMED), Tokyo, Japan.
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Hayakawa-Yano Y, Suyama S, Nogami M, Yugami M, Koya I, Furukawa T, Zhou L, Abe M, Sakimura K, Takebayashi H, Nakanishi A, Okano H, Yano M. An RNA-binding protein, Qki5, regulates embryonic neural stem cells through pre-mRNA processing in cell adhesion signaling. Genes Dev 2017; 31:1910-1925. [PMID: 29021239 PMCID: PMC5693031 DOI: 10.1101/gad.300822.117] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2017] [Accepted: 09/14/2017] [Indexed: 01/07/2023]
Abstract
Cell type-specific transcriptomes are enabled by the action of multiple regulators, which are frequently expressed within restricted tissue regions. In the present study, we identify one such regulator, Quaking 5 (Qki5), as an RNA-binding protein (RNABP) that is expressed in early embryonic neural stem cells and subsequently down-regulated during neurogenesis. mRNA sequencing analysis in neural stem cell culture indicates that Qki proteins play supporting roles in the neural stem cell transcriptome and various forms of mRNA processing that may result from regionally restricted expression and subcellular localization. Also, our in utero electroporation gain-of-function study suggests that the nuclear-type Qki isoform Qki5 supports the neural stem cell state. We next performed in vivo transcriptome-wide protein-RNA interaction mapping to search for direct targets of Qki5 and elucidate how Qki5 regulates neural stem cell function. Combined with our transcriptome analysis, this mapping analysis yielded a bona fide map of Qki5-RNA interaction at single-nucleotide resolution, the identification of 892 Qki5 direct target genes, and an accurate Qki5-dependent alternative splicing rule in the developing brain. Last, our target gene list provides the first compelling evidence that Qki5 is associated with specific biological events; namely, cell-cell adhesion. This prediction was confirmed by histological analysis of mice in which Qki proteins were genetically ablated, which revealed disruption of the apical surface of the lateral wall in the developing brain. These data collectively indicate that Qki5 regulates communication between neural stem cells by mediating numerous RNA processing events and suggest new links between splicing regulation and neural stem cell states.
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Affiliation(s)
- Yoshika Hayakawa-Yano
- Division of Neurobiology and Anatomy, Graduate School of Medical and Dental Sciences, Niigata University, Asahimachidori, Chuo-ku, Niigata, Niigata 951-8510, Japan
| | - Satoshi Suyama
- Department of Physiology, Keio University School of Medicine, Shinjuku-ku, Tokyo 160-8582, Japan
| | - Masahiro Nogami
- Shonan Incubation Laboratories, Pharmaceutical Research Division, Takeda Pharmaceutical Company Limited, Fujisawa, Kanagawa 251-8555, Japan.,Integrated Technology Research Laboratories, Pharmaceutical Research Division, Takeda Pharmaceutical Company Limited, Fujisawa, Kanagawa 251-8555, Japan
| | - Masato Yugami
- Shonan Incubation Laboratories, Pharmaceutical Research Division, Takeda Pharmaceutical Company Limited, Fujisawa, Kanagawa 251-8555, Japan.,Integrated Technology Research Laboratories, Pharmaceutical Research Division, Takeda Pharmaceutical Company Limited, Fujisawa, Kanagawa 251-8555, Japan
| | - Ikuko Koya
- Department of Physiology, Keio University School of Medicine, Shinjuku-ku, Tokyo 160-8582, Japan
| | - Takako Furukawa
- Division of Neurobiology and Anatomy, Graduate School of Medical and Dental Sciences, Niigata University, Asahimachidori, Chuo-ku, Niigata, Niigata 951-8510, Japan
| | - Li Zhou
- Department of Cellular Neurobiology, Brain Research Institute, Niigata University, Asahimachidori, Chuo-ku, Niigata, Niigata 951-8585, Japan
| | - Manabu Abe
- Department of Cellular Neurobiology, Brain Research Institute, Niigata University, Asahimachidori, Chuo-ku, Niigata, Niigata 951-8585, Japan
| | - Kenji Sakimura
- Department of Cellular Neurobiology, Brain Research Institute, Niigata University, Asahimachidori, Chuo-ku, Niigata, Niigata 951-8585, Japan
| | - Hirohide Takebayashi
- Division of Neurobiology and Anatomy, Graduate School of Medical and Dental Sciences, Niigata University, Asahimachidori, Chuo-ku, Niigata, Niigata 951-8510, Japan
| | - Atsushi Nakanishi
- Shonan Incubation Laboratories, Pharmaceutical Research Division, Takeda Pharmaceutical Company Limited, Fujisawa, Kanagawa 251-8555, Japan.,Integrated Technology Research Laboratories, Pharmaceutical Research Division, Takeda Pharmaceutical Company Limited, Fujisawa, Kanagawa 251-8555, Japan
| | - Hideyuki Okano
- Department of Physiology, Keio University School of Medicine, Shinjuku-ku, Tokyo 160-8582, Japan
| | - Masato Yano
- Division of Neurobiology and Anatomy, Graduate School of Medical and Dental Sciences, Niigata University, Asahimachidori, Chuo-ku, Niigata, Niigata 951-8510, Japan.,Department of Physiology, Keio University School of Medicine, Shinjuku-ku, Tokyo 160-8582, Japan
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Gupta V, Liu S, Ando H, Ishii R, Tateno S, Kaneko Y, Yugami M, Sakamoto S, Yamaguchi Y, Nureki O, Handa H. Salicylic Acid Induces Mitochondrial Injury by Inhibiting Ferrochelatase Heme Biosynthesis Activity. Mol Pharmacol 2013; 84:824-33. [DOI: 10.1124/mol.113.087940] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
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Yugami M, Kabe Y, Yamaguchi Y, Wada T, Handa H. hnRNP-U enhances the expression of specific genes by stabilizing mRNA. FEBS Lett 2006; 581:1-7. [PMID: 17174306 PMCID: PMC7130276 DOI: 10.1016/j.febslet.2006.11.062] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2006] [Revised: 11/20/2006] [Accepted: 11/24/2006] [Indexed: 11/18/2022]
Abstract
Heterogeneous nuclear ribonucleoproteins (hnRNPs) are thought to be involved in pre-mRNA processing. hnRNP-U, also termed scaffold attachment factor A (SAF-A), binds to pre-mRNA and nuclear matrix/scaffold attachment region DNA elements. However, its role in the regulation of gene expression is as yet poorly understood. In the present study, we show that hnRNP-U specifically enhances the expression of tumor necrosis factor alpha mRNA by increasing its stability, possibly through binding to the 3' untranslated region. We also show that hnRNP-U enhances the expression of several other genes as well, including GADD45A, HEXIM1, HOXA2, IER3, NHLH2, and ZFY, by binding to and stabilizing these mRNAs. These results suggest that hnRNP-U enhances the expression of specific genes by regulating mRNA stability.
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Affiliation(s)
- Masato Yugami
- Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology, Yokohama, Kanagawa, Japan
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Shima D, Yugami M, Tatsuno M, Wada T, Yamaguchi Y, Handa H. Mechanism of H-8 inhibition of cyclin-dependent kinase 9: study using inhibitor-immobilized matrices. Genes Cells 2003; 8:215-23. [PMID: 12622719 DOI: 10.1046/j.1365-2443.2003.00627.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
BACKGROUND Positive transcription elongation factor b (P-TEFb), which phosphorylates the carboxyl-terminal domain (CTD) of RNA polymerase II (RNAPII), is comprised of the catalytic subunit cyclin-dependent kinase 9 (CDK9) and the regulatory subunit cyclin T. The kinase activity and transcriptional activation potential of P-TEFb is sensitive to various compounds, including H-8, 5,6-dichloro-1-beta-d-ribofuranosylbenzimidazole (DRB), and flavopiridol. RESULTS We investigated the molecular mechanism of the H-8 inhibition of CDK9 using matrices to which H-9, an amino derivative of H-8, was immobilized. CDK9 bound specifically to H-9, and this interaction was competitively inhibited by ATP and DRB, but not by flavopiridol. Mutational analyses demonstrated that the central region of CDK9, which encompasses the T-loop region, was important for its binding to H-9. CONCLUSIONS H-9-immobilized latex beads are useful for trapping CDK9 and a subset of kinases from crude cell extracts. The flavopiridol-binding region of CDK9 is most likely different from its H-9-binding region. These biochemical data support previously reported observations which were based on crystallographic data.
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Affiliation(s)
- Daisuke Shima
- Faculty of Bioscience and Biotechnology, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama 226-8501, Japan
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