Hironori Aramaki

Publications (2)12.62 Total impact

• Source

  Available from: Sanae Ishijima

  Article: Transcription regulation by feast/famine regulatory proteins, FFRPs, in archaea and eubacteria.

  Tsuyoshi Kawashima, Hironori Aramaki, Tomoya Oyamada, Kozo Makino, Mitsugu Yamada, Hideyasu Okamura, Katsushi Yokoyama, Sanae Arakawa Ishijima, Masashi Suzuki
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  ABSTRACT: Feast/famine regulatory proteins (FFRPs) comprise a single group of transcription factors systematically distributed throughout archaea and eubacteria. In the eubacterial domain in Escherichia coli, autotrophic pathways are activated and heterotrophic pathways are repressed by an FFRP, the leucine-responsive regulatory protein (Lrp), in some cases in interaction with other transcription factors. By sensing the concentration of leucine, Lrp changes its association state between hexadecamers and octamers to adapt the autotrophic or heterotrophic mode. The lrp gene is regulated so that the concentration of Lrp decreases in the presence of rich nutrition. In the archaeal domain a large part of the metabolism of Pyrococcus OT3 is regulated by another FFRP, FL11. In the presence of rich nutrition, the metabolism is released from repression by FL11; transcription of fl11 is terminated by FL11 forming octamers in interaction with lysine. When the nutrient is depleted, the metabolism is arrested by a high concentration of FL11; FL11 disassembles to dimers in the absence of lysine, and repression of transcription of fl11 is relaxed. Common characteristics of the master regulations by FL11 and Lrp hint at the prototype regulation once achieved in the common ancestor of all extant organisms. Mechanisms of discrimination by FFRPs between DNA sequences and also between co-regulatory molecules, mostly amino acids, and variations of transcription regulations observed with archaea and eubacteria are reviewed.
  Biological & Pharmaceutical Bulletin 03/2008; 31(2):173-86. · 1.66 Impact Factor
• Source

  Available from: Sanae Ishijima

  Article: Feast/famine regulatory proteins (FFRPs): Escherichia coli Lrp, AsnC and related archaeal transcription factors.

  Katsushi Yokoyama, Sanae A Ishijima, Lester Clowney, Hideaki Koike, Hironori Aramaki, Chikako Tanaka, Kozo Makino, Masashi Suzuki
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  ABSTRACT: Feast/famine regulatory proteins comprise a diverse family of transcription factors, which have been referred to in various individual identifications, including Escherichia coli leucine-responsive regulatory protein and asparagine synthase C gene product. A full length feast/famine regulatory protein consists of the N-terminal DNA-binding domain and the C-domain, which is involved in dimerization and further assembly, thereby producing, for example, a disc or a chromatin-like cylinder. Various ligands of the size of amino acids bind at the interface between feast/famine regulatory protein dimers, thereby altering their assembly forms. Also, the combination of feast/famine regulatory protein subunits forming the same assembly is altered. In this way, a small number of feast/famine regulatory proteins are able to regulate a large number of genes in response to various environmental changes. Because feast/famine regulatory proteins are shared by archaea and eubacteria, the genome-wide regulation by feast/famine regulatory proteins is traceable back to their common ancestor, being the prototype of highly differentiated transcription regulatory mechanisms found in organisms nowadays.
  FEMS Microbiology Reviews 02/2006; 30(1):89-108. · 10.96 Impact Factor