Publications by authors named "Kazunori Tomita"

Stress induces global stabilization of the mRNA poly(A) tail (PAT) and the assembly of untranslated poly(A)-tailed mRNA into mRNPs that accumulate in stress granules (SGs). While the mechanism behind stress-induced global PAT stabilization has recently emerged, the biological significance of PAT stabilization under stress remains elusive. Here, we demonstrate that stress-induced PAT stabilization is a prerequisite for SG formation.

View Article and Find Full Text PDF

Age is a major risk factor for neurodegenerative diseases. Shortening of leucocyte telomeres with advancing age, arguably a measure of "biological" age, is a known phenomenon and epidemiologically correlated with age-related disease. The main mechanism of telomere shortening is cell division, rendering telomere length in post-mitotic cells presumably stable.

View Article and Find Full Text PDF

Loss of proteostasis is a fundamental process driving aging. Proteostasis is affected by the accuracy of translation, yet the physiological consequence of having fewer protein synthesis errors during multi-cellular organismal aging is poorly understood. Our phylogenetic analysis of RPS23, a key protein in the ribosomal decoding center, uncovered a lysine residue almost universally conserved across all domains of life, which is replaced by an arginine in a small number of hyperthermophilic archaea.

View Article and Find Full Text PDF

To avoid replicative senescence or telomere-induced apoptosis, cancers employ telomere maintenance mechanisms (TMMs) involving either the upregulation of telomerase or the acquisition of recombination-based alternative telomere lengthening (ALT). The choice of TMM may differentially influence cancer evolution and be exploitable in targeted therapies. Here, we examine TMMs in a panel of 17 osteosarcoma-derived cell lines, defining three separate groups according to TMM and the length of telomeres maintained.

View Article and Find Full Text PDF

RNA modifications play a fundamental role in cellular function. Pseudouridylation, the most abundant RNA modification, is catalyzed by the H/ACA small ribonucleoprotein (snoRNP) complex that shares four core proteins, dyskerin (DKC1), NOP10, NHP2, and GAR1. Mutations in , , or cause dyskeratosis congenita (DC), a disorder characterized by telomere attrition.

View Article and Find Full Text PDF

Telomerase, the enzyme that replenishes telomeres, is essential for most eukaryotes to maintain their generations. Telomere length homeostasis is achieved via a balance between telomere lengthening by telomerase, and erosion over successive cell divisions. Impaired telomerase regulation leads to shortened telomeres and can cause defects in tissue maintenance.

View Article and Find Full Text PDF

Understanding the intricacies of telomerase regulation is crucial due to the potential health benefits of modifying its activity. Telomerase is composed of an RNA component and reverse transcriptase. However, additional factors required during biogenesis vary between species.

View Article and Find Full Text PDF

Shelterin, the telomeric protein complex, plays a crucial role in telomere homeostasis. In fission yeast, telomerase is recruited to chromosome ends by the shelterin component Tpz1 and its binding partner Ccq1, where telomerase binds to the 3' overhang to add telomeric repeats. Recruitment is initiated by the interaction of Ccq1 with the telomerase subunit Est1.

View Article and Find Full Text PDF

During meiotic prophase, chromosome arrangement and oscillation promote the pairing of homologous chromosomes for meiotic recombination. This dramatic movement involves clustering of telomeres at the nuclear membrane to form the so-called telomere bouquet. In fission yeast, the telomere bouquet is formed near the spindle pole body (SPB), which is the microtubule organising centre, functionally equivalent to the metazoan centrosome.

View Article and Find Full Text PDF

Aberrant activation of telomerase occurs in 85-90% of all cancers and underpins the ability of cancer cells to bypass their proliferative limit, rendering them immortal. The activity of telomerase is tightly controlled at multiple levels, from transcriptional regulation of the telomerase components to holoenzyme biogenesis and recruitment to the telomere, and finally activation and processivity. However, studies using cancer cell lines and other model systems have begun to reveal features of telomeres and telomerase that are unique to cancer.

View Article and Find Full Text PDF

Background: Fission yeast is one of the most commonly used model organisms for studying genetics. For selection of desirable genotypes, antibiotic resistance cassettes are widely integrated into the genome near genes of interest. In yeasts, this is achieved by PCR amplification of the cassette flanked by short homology sequences, which can be incorporated by homology directed repair.

View Article and Find Full Text PDF

Obesity is known to be associated with the development of heart failure (HF). However, the relationship between the body mass index (BMI) and acute HF (AHF) remains to be elucidated. Eight hundred and eight AHF patients were enrolled in this study.

View Article and Find Full Text PDF

Background: No cardiac biomarkers for detecting acute kidney injury (AKI) on admission in non-surgical intensive care patients have been reported. The aim of the present study is to elucidate the role of cardiac biomarkers for quickly identifying the presence of AKI on admission.

Methods: Data for 1183 patients who underwent the measurement of cardiac biomarkers, including the serum heart-type fatty acid-binding protein (s-HFABP) level, in the emergency department were screened, and 494 non-surgical intensive care patients were enrolled in this study.

View Article and Find Full Text PDF

Understanding the mechanisms of chromosomal double-strand break repair (DSBR) provides insight into genome instability, oncogenesis and genome engineering, including disease gene correction. Research into DSBR exploits rare-cutting endonucleases to cleave exogenous reporter constructs integrated into the genome. Multiple reporter constructs have been developed to detect various DSBR pathways.

View Article and Find Full Text PDF

Background: Chromosomes reorganize in early meiotic prophase to form the so-called telomere bouquet. In fission yeast, telomeres localize to the nuclear periphery via interaction of the telomeric protein Rap1 with the membrane protein Bqt4. During meiotic prophase, the meiotic proteins Bqt1-2 bind Rap1 and tether to the spindle pole body to form the bouquet.

View Article and Find Full Text PDF

Telomeres and centromeres have traditionally been considered to perform distinct roles. During meiotic prophase, in a conserved chromosomal configuration called the bouquet, telomeres gather to the nuclear membrane (NM), often near centrosomes. We found previously that upon disruption of the fission yeast bouquet, centrosomes failed to insert into the NM at meiosis I and nucleate bipolar spindles.

View Article and Find Full Text PDF

Background: Different mechanisms of acute kidney injury (AKI) may exist for acute heart failure (AHF) patients compared with other patients.

Methods And Results: We analyzed data from 282 patients with AHF. The biomarkers were measured within 30 min of admission.

View Article and Find Full Text PDF

Current models depict that telomerase recruitment equates to activation. Telomeric DNA-binding proteins and the telomerase accessory proteins coordinate the recruitment of telomerase to the ends of chromosomes in a telomere length- and cell-cycle-dependent manner [1-4]. Recent studies have demonstrated that the telomeric protein TPP1 and its binding protein TIN2 are key proteins for both telomerase recruitment and processivity in mammalian cells [5-7].

View Article and Find Full Text PDF

Background: Biomarkers predicting adverse outcomes in non-surgical intensive care patients have not been reported.

Methods And Results: Data for 1,006 emergency department patients were prospectively analyzed. The serum heart-type fatty acid-binding protein (s-H-FABP) level was measured within 10 min of admission.

View Article and Find Full Text PDF

Background: No scoring system for assessing acute heart failure (AHF) has been reported.

Methods And Results: Data for 824 AHF patients were analyzed. The subjects were divided into an alive (n=750) and a dead group (n=74).

View Article and Find Full Text PDF

Complicated respiratory failure requiring mechanical ventilation in patients with type-B acute aortic dissection (AAD) has been previously reported, and inflammatory reactions have been found to be associated with the occurrence of oxygenation impairment (OI). However, the possibility of predicting the occurrence of OI in patients with type-B AAD has not yet been evaluated. This study was performed to investigate the possibility of predicting the occurrence of OI in type-B AAD.

View Article and Find Full Text PDF

Background:  Tolvaptan, an oral selective vasopressin 2 receptor antagonist that acts on the distal nephrons to cause a loss of electrolyte-free water, is rarely used during the acute phase of acute heart failure (AHF).

Methods And Results:  We investigated 183 AHF patients admitted to the intensive care unit and administered tolvaptan (7.5mg) with continuous intravenous furosemide, and then additionally at 12-h intervals until HF was compensated.

View Article and Find Full Text PDF

There have been few reports discussing the clinical significance of the season of admission of acute heart failure (AHF) patients. The data of 661 patients with AHF admitted to the intensive care unit were analyzed. Patients were assigned to a summer admission (Group-S, n = 113, between July and September), a winter admission (Group-W, n = 214, between December and February), or to the other seasons admission group (Group-O, n = 334).

View Article and Find Full Text PDF

Aim Of The Study: Cardiopulmonary resuscitation and mild therapeutic hypothermia (MTH) have improved neurological outcomes after sudden cardiac arrest, but the factors affecting favorable neurological outcome remain unclear. The aim of this study was to clarify these factors in patients in cardiac arrest treated with MTH.

Methods: Forty-six consecutive patients (mean age, 59.

View Article and Find Full Text PDF