This work was supported by grants from the Japanese Ministry of Education, Culture, Sports, Science and Technology (17K08823, Nishiyama and 16H05187, Matsumoto), the Research Program on Emerging and Re-emerging Infectious Diseases, and the Research Program on the Challenges of Global Health Issues (U.S.-Japan Cooperative Medical Sciences Program) from Japan Agency for Medical Research and Development, AMED. Author Contributions Conceptualization: A.S., A.N. Introduction Histone is a primary component of Rabbit Polyclonal to FOXO1/3/4-pan (phospho-Thr24/32) the eukaryotic nucleosome, where DNA wraps around an octamer of four core histones (two of each histone H2A, H2B, H3, and H4). Linker histones (H1 and H5) bind to the nucleosome and adjacent linker DNA. These histones possess intrinsically disordered regions (IDR), which lack typical secondary and tertiary structures1. Discoveries of IDR and their high TEPP-46 frequency in eukaryotic proteins, especially nuclear proteins2,3, have been challenging the doctrine of traditional structure-function paradigm. For instance, polycationic C-terminal IDR of histone H1 binds to DNA or negatively charged protein TEPP-46 domains. The interaction with the targets induces the secondary structures (e.g., -helixes) in IDR, resulting in the formation of stable folding and oligomerization of chromatin fibers1,4C7. IDR of the histones play significant roles in genome functions through chromatin condensation, leading to regulation of transcription, replication, and recombination8C10. The bacterial chromosome is also folded into a compact structure, called nucleoid. Bacterial histone-like proteins, such as HU (initially reported as a heat stable DNA-binding protein of strain U93)11, integration host factor TEPP-46 (IHF)12, and histone-like nucleoid structuring protein (H-NS)13 are small basic proteins (10C15?kDa), which share functions with histones, especially in the DNA-compaction capacity14,15. HU is one of the most extensively studied histone-like proteins and has been found to be conserved in all sequenced eubacteria11,14C16. It exists as a hetero- or homodimer (e.g., HU and HU in and and 21?kDa in MDP1 TEPP-46 (MDP1Mtb) has revealed a repeat of two -helices at the N-terminus (contributing to dimerization), followed by a -sheet domain which forms a DNA-binding arm (Fig.?1)19. In contrast, more than 100-amino acid C-terminal domain possesses characteristics of IDR that is rich in Lys, Ala, and Pro residues and composed of short sequence repeats such as, PAKK1,14,17. Except for a few -helices, there is no typical secondary structure in the C-terminal half from Pro100 of both MDP1Mtb and MDP1, as shown by PSIPRED, the structure prediction software (Supplementary Fig.?S1). Open in a separate window Figure 1 Alignment of amino acid sequences of MDP1 from mycobacterial species and HU. Amino acid sequences of MDP1 in 4 mycobacterial species, a BCG vaccine strain, HU and HU are aligned. Secondary structures of the N-terminal TEPP-46 99 amino acid region of MDP1Mtb19 are presented as helices (indicated as tubes) and strands (indicated as arrows) at the top of the alignment. The black vertical line between 99th and 100th amino acid residues indicates a boundary of NTD and C-terminal IDR which was suggested previously19. Aligned sequences are as follows: Mtb_Rv2986c, H37Rv MDP1 (Rv2986c, MDP1Mtb); Mbo_Mb3010c, AF2122/97 MDP1 (Mb3010c); BCG_JTY3002, BCG strain Tokyo MDP1 (JTY3002); Msm_MSMEG_2389, mc2_155 MDP1 (MSMEG2389); Mle_ML1683, TN MDP1 (ML1683); Eco_CUU96508, 10270 HU (“type”:”entrez-protein”,”attrs”:”text”:”CUU96508″,”term_id”:”1002335541″CUU96508); and Bsu_CUB51197, JRS10 HU (“type”:”entrez-protein”,”attrs”:”text”:”CUB51197″,”term_id”:”924100295″CUB51197). MDP1 is an abundant protein in mycobacterial cells and is considered to play pivotal roles in mycobacterial genome functions. In the previous study, we found suppressive effects of MDP1 on the macromolecular biosynthesis of DNA and RNA in cell-free assay and bacterial growth under MDP1 overexpression18,20. Mukherjee studies implicated the importance of IDR in the function of MDP1. In order to know more precise functions of MDP1-IDR, we created genomic MDP1-gene-deficient strains, which inducibly express intact MDP1 or only NTD of MDP1, and MDP1-conditional knock-down strains. By employing these strains, we observed that IDR of MDP1 is critical for MDP1-related phenotypes of cell, including genome compaction, suppression of DNA synthesis, and drug tolerance to isoniazid, a front line tuberculosis drug. This study provides a reasonable basis.
This work was supported by grants from the Japanese Ministry of Education, Culture, Sports, Science and Technology (17K08823, Nishiyama and 16H05187, Matsumoto), the Research Program on Emerging and Re-emerging Infectious Diseases, and the Research Program on the Challenges of Global Health Issues (U