Endogenous chondroitin extends the lifespan and healthspan in C. elegans.

Chondroitin, a class of glycosaminoglycan polysaccharides, is found as proteoglycans in the extracellular matrix, plays a crucial role in tissue morphogenesis during development and axonal regeneration. Ingestion of chondroitin prolongs the lifespan of C. elegans.

Inhibition of Transglutaminase 2 Reduces Peritoneal Injury in a Chlorhexidine-Induced Peritoneal Fibrosis Model.

Long-term peritoneal dialysis (PD) is often associated with peritoneal dysfunction leading to withdrawal from PD. The characteristic pathologic features of peritoneal dysfunction are widely attributed to peritoneal fibrosis and angiogenesis. The detailed mechanisms remain unclear, and treatment targets in clinical settings have yet to be identified.

A synthetic synaptic organizer protein restores glutamatergic neuronal circuits.

Neuronal synapses undergo structural and functional changes throughout life, which are essential for nervous system physiology. However, these changes may also perturb the excitatory-inhibitory neurotransmission balance and trigger neuropsychiatric and neurological disorders. Molecular tools to restore this balance are highly desirable.

Applications of bottom-up human artificial chromosomes in cell research and cell engineering.

Chromosome manipulation is a useful technique in biological science. We have constructed human artificial chromosomes (HACs) based on the transfection of centromeric alphoid DNA precursors into cultured human cells. Moreover, HAC-based technology has been developed into a novel gene expression vector tool for introducing large-size genomic DNA.

Improving the efficiency of gene insertion in a human artificial chromosome vector and its transfer in human-induced pluripotent stem cells.

A human artificial chromosome (HAC) vector has potential to overcome the problems of stable gene expression associated with plasmid, transposon, and virus-based vectors, such as insertional mutagenesis, position effect, uncontrollable copy number, unstable gene expression, and DNA size limitation. The main advantages of the HAC are its episomal nature and ability to accommodate DNA inserts of any size. However, HAC vectors have two disadvantages: low efficiency of gene insertion and lack of reports regarding the successful HAC transfer to human-induced pluripotent stem cells (iPSCs).

Generating a transgenic mouse line stably expressing human MHC surface antigen from a HAC carrying multiple genomic BACs.

The human artificial chromosome (HAC) vector is a promising tool to improve the problematic suppression and position effects of transgene expression frequently seen in transgenic cells and animals produced by conventional plasmid or viral vectors. We generated transgenic mice maintaining a single HAC vector carrying two genomic bacterial artificial chromosomes (BACs) from human HLA-DR loci (DRA and DRB1). Both transgenes on the HAC in transgenic mice exhibited tissue-specific expression in kidney, liver, lung, spleen, lymph node, bone marrow, and thymus cells in RT-PCR analysis.

A novel mouse model for Down syndrome that harbor a single copy of human artificial chromosome (HAC) carrying a limited number of genes from human chromosome 21.

Down syndrome (DS), also known as Trisomy 21, is the most common chromosome aneuploidy in live-born children and displays a complicated symptom. To date, several kinds of mouse models have been generated to understand the molecular pathology of DS, yet the gene dosage effects and gene(s)-phenotype(s) correlation are not well understood. In this study, we established a novel method to generate a partial trisomy mice using the mouse ES cells that harbor a single copy of human artificial chromosome (HAC), into which a small human DNA segment containing human chromosome 21 genes cloned in a bacterial artificial chromosome (BAC) was recombined.

LINE1 family member is negative regulator of HLA-G expression.

Class Ia molecules of human leucocyte antigen (HLA-A, -B and -C) are widely expressed and play a central role in the immune system by presenting peptides derived from the lumen of the endoplasmic reticulum. In contrast, class Ib molecules such as HLA-G serve novel functions. The distribution of HLA-G is mostly limited to foetal trophoblastic tissues and some tumour tissues.

Construction and use of a bottom-up HAC vector for transgene expression.

Recent technological advances have enabled visualization of the organization and dynamics of local -chromatin structures; however, the global mechanisms by which chromatin organization modulates gene regulation are poorly understood. We designed and constructed a human artificial chromosome (HAC) vector that allows regulation of transgene expression and delivery of a gene expression platform into many vertebrate cell lines. This technology for manipulating a transgene using a HAC vector could be used in applied biology.

Cell to cell transfer of the chromatin-packaged human beta-globin gene cluster.

Cell type-specific gene expression is regulated by chromatin structure and the transcription factors provided by the cells. In the present study, we introduced genes packaged into chromatin into target cells using a human artificial chromosome (HAC) and analyzed regulation of gene expression. The human beta-globin gene cluster was built into an HAC (globin-HAC) and introduced into mouse embryonic stem (ES) cells using microcell-mediated chromosome transfer (MMCT); the adult-type human beta-globin gene was expressed in bone marrow and spleen cells of the transgenic mice.

CENP-O, a protein localized at the centromere throughout the cell cycle, is a novel target antigen in systemic sclerosis.

Objective: CENP-A, -B, and -C are major centromere components and the main targets of anticentromere antibodies (ACA). Many other proteins are also assembled around CENP-A nucleosomes in interphase nuclei to form the interphase centromere complex (ICEN). The CENP-O protein is a component of the ICEN that localizes at the centromere throughout the cell cycle.

Manipulating transgenes using a chromosome vector.

Recent technological advances have enabled us to visualize the organization and dynamics of local chromatin structures; however, the comprehensive mechanisms by which chromatin organization modulates gene regulation are poorly understood. We designed a human artificial chromosome vector that allowed manipulation of transgenes using a method for delivering chromatin architectures into different cell lines from human to fish. This methodology enabled analysis of de novo construction, epigenetic maintenance and changes in the chromatin architecture of specific genes.

Immortalized hepatocytes using human artificial chromosome.

The shortage of organ donors has impeded the development of human hepatocyte transplantation. Immortalized hepatocytes could provide an unlimited supply of transplantable cells. To determine whether immortalized hepatocytes could provide global metabolic support in end-stage liver disease, rat hepatocyte clones were developed by transduction with the gene encoding the Simian virus 40 T antigen (SVT) using the human artificial minichromosome (HAC).

Human artificial chromosomes constructed using the bottom-up strategy are stably maintained in mitosis and efficiently transmissible to progeny mice.

Human artificial chromosomes (HACs) are alternative vectors that promise to overcome problematic transgene expression often occurring with conventional vectors in mammalian cells and bodies. We have successfully generated HACs by multimerization of a cloned long alphoid stretch in a human cell line, HT1080. Furthermore, we developed technologies for cloning large genomic regions into HACs by means of co-transfection of clones with the alphoid array and clones encoding the genomic region of interest.

Dicer is essential for formation of the heterochromatin structure in vertebrate cells.

RNA interference is an evolutionarily conserved gene-silencing pathway in which the nuclease Dicer cleaves double-stranded RNA into small interfering RNAs. The biological function of the RNAi-related pathway in vertebrate cells is not fully understood. Here, we report the generation of a conditional loss-of-function Dicer mutant in a chicken-human hybrid DT40 cell line that contains human chromosome 21.

Generation of human artificial chromosomes expressing naturally controlled guanosine triphosphate cyclohydrolase I gene.

Background: Human artificial chromosomes (HACs) are generated from the precursor DNA constructs containing alpha-satellite DNA with CENP-B boxes, and the process could be used for the incorporation of large genes in the HACs. Guanosine triphosphate cyclohydrolase I (GCH1) is the first and rate-limiting enzyme for the biosynthesis of tetrahydrobiopterin, the essential co-factor of aromatic amino acid hydroxylases and nitric oxide synthase.

Results: We constructed HACs carrying a 180 kb genome segment encoding the human GCH1 gene and its control region from the bacterial artificial chromosome (BAC) with the GCH1 segment by co-transfection with the alpha-satellite DNA-containing BAC to a human fibroblast cell line.