Ryugaku Jinja · Professor Archive
Public Professor Archive
Toshiyuki GOTO後藤 俊志
Kobe University · Graduate School of Science and Technology Innovation
- Publications
- 4
- Projects
- 1
留学
神社Kobe University · Graduate School of Science and Technology Innovation
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- Microtubule array observed in the posterior-vegetal cortex during cytoplasmic and cortical reorganization of the ascidian egg.Body axis formation during embryogenesis results from asymmetric localization of maternal factors in the egg. Shortly before the first cleavage in ascidian eggs, cell polarity along the anteroposterior (A-P) axis is established and the cytoplasmic domain (myoplasm) relocates from the vegetal to the posterior region in a microtubule-dependent manner. Through immunostaining, tubulin accumulation during this reorganization is observable on the myoplasm cortex. However, more detailed morphological features of microtubules remain relatively unknown. In this study, we invented a new reagent that improves the immunostaining of cortical microtubules and successfully visualized a parallel array of thick microtubules. During reorganization, they covered nearly the entire myoplasm cortical region, beneath the posterior-vegetal cortex. We designated this microtubule array as CAMP (cortical array of microtubules in posterior vegetal region). During the late phase of reorganization, CAMP shrank and the myoplasm formed a crescent-like cytoplasmic domain. When the CAMP formation was inhibited by sodium azide, myoplasmic reorganization and A-P axis formation were both abolished, suggesting that CAMP is important for these two processes.
- Loss of p53 Provokes NF-κB-Dependent Disruption of Nucleolar Cap and Nucleoplasmic Redistribution of Fibrillarin During Nucleolar Stress.Chemotherapeutic agents targeting ribosome biogenesis induce profound reorganization of nucleolar architecture, yet how the tumor suppressor p53 governs these structural responses remains unclear. Here, we show that loss of p53 leads to NF-κB-dependent disappearance of nucleolar caps induced by doxorubicin (DOXO). Under these conditions, fibrillarin (FBL), which is normally confined to the nucleolus, relocates to the nucleoplasm and forms foci that partially associate with G-quadruplex (G4) structures, non-canonical nucleic acid secondary structures enriched at transcriptionally active genomic regions. To examine whether this redistribution is linked to transcriptional changes, we integrated publicly available transcriptomic datasets and identified genes that were upregulated in p53-deficient cells under DOXO treatment and downregulated upon FBL depletion. Given that casein kinase 2 alpha (CK2α) is a nuclear binding partner of FBL, we further analyzed CK2α-dependent gene programs. This analysis revealed that a fraction of FBL-responsive genes overlapped with CK2α-dependent signatures and were enriched for promoter-proximal G4 structures. Among candidate regulators, the G4-binding transcription factor MAZ emerged as a potential mediator linking nucleoplasmic FBL and CK2α to G4-associated transcriptional regulation. Together, our findings identify a mechanism linking loss of p53 to G4-associated transcriptional reprogramming through nucleolar architectural disruption mediated by an FBL-CK2α-MAZ axis during DOXO treatment.
- Comparison of Evolutionary Relationships between Branchiostoma floridae, Ciona intestinalis, and Homo sapiens Globins Provide Evidence of Gene Co-Option and Convergent Evolution.Globins have been studied as model proteins to elucidate the principles of protein evolution. This was achieved by understanding the relationship between amino acid sequence, three-dimensional structure, physicochemical properties, and physiological function. Previous molecular phylogenies of chordate globin genes revealed the monophyletic evolution of urochordate globins and suggested convergent evolution. However, to provide evidence of convergent evolution, it is necessary to determine the physicochemical and functional similarities between vertebrates and urochordate globins. In this study, we determined the expression patterns of Ciona globin genes using real-time RT-PCR. Two genes (Gb-1 and Gb-2) were predominantly expressed in the branchial sac, heart, and hemocytes and were induced under hypoxia. Combined with the sequence analysis, our findings suggest that Gb-1/-2 correspond to vertebrate hemoglobin-α/-β. However, we did not find a robust similarity between Gb-3, Gb-4, and vertebrate globins. These results suggested that, even though Ciona globins obtained their unique functions differently from vertebrate globins, the two of them shared some physicochemical features and physiological functions. Our findings offer a good example for understanding the molecular mechanisms underlying gene co-option and convergence, which could lead to evolutionary innovations.
- Metabolomic profiling of cancer-related fatigue involved in cachexia and chemotherapy.Patients with advanced cancer are frequently burdened with a severe sensation of fatigue called cancer-related fatigue (CRF). CRF is induced at various stages and treatments, such as cachexia and chemotherapy, and reduces the overall survival of patients. Objective and quantitative assessment of CRF could contribute to the diagnosis and prediction of treatment efficacy. However, such studies have not been intensively performed, particularly regarding metabolic profiles. Here, we conducted plasma metabolomics of 15 patients with urological cancer. The patients with and without fatigue, including those with cachexia or chemotherapy-induced fatigue, were compared. Significantly lower concentrations of valine and tryptophan were observed in fatigued patients than in non-fatigued patients. In addition, significantly higher concentrations of polyamine pathway metabolites were observed in patients with fatigue and cachexia than in those without cachexia. Patients with exacerbated fatigue due to chemotherapy showed significantly decreased cysteine and methionine metabolism before chemotherapy compared with those without fatigue exacerbation. These findings suggest that plasma metabolic profiles could help improve the diagnosis and monitoring of CRF.
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