Erratum: Dendritic spine formation and synapse maturation in transcription factor-induced human iPSC-derived neurons.

[This corrects the article DOI: 10.1016/j.isci.

Dendritic spine formation and synapse maturation in transcription factor-induced human iPSC-derived neurons.

Synaptic maturation is reportedly limited in human induced pluripotent stem cell (iPSC)-derived neurons. Notably, their ability to reach postnatal-like stages and form dendritic spines has been difficult to demonstrate unless using long-term cultured organoids. Recent transcription factor (TF)-based induction methods allow the accelerated generation of differentiated neurons, which offers an unprecedented opportunity to address further progression into late developmental stages.

Development of fibrin hydrogel-based in vitro bioassay system for assessment of skin permeability to and pro-inflammatory activity mediated by zinc ion released from nanoparticles.

Nanoparticles (NPs) are promising products in industry and medicine due to their unique physicochemical properties. In particular, zinc oxide (ZnO) NPs are extensively incorporated into sunscreens to protect the skin from exposure to ultraviolet radiation. However, there are several health concerns about skin penetration and the resultant toxicity.

High-precision three-dimensional inkjet technology for live cell bioprinting.

In recent years, bioprinting has emerged as a promising technology for the construction of three-dimensional (3D) tissues to be used in regenerative medicine or screening applications. In the present study, we present the development of an inkjet-based bioprinting system to arrange multiple cells and materials precisely into structurally organized constructs. A novel inkjet printhead has been specially designed for live cell ejection.

Novel Bioprinting Application for the Production of Reference Material Containing a Defined Copy Number of Target DNA.

Nucleic acid amplification methods, such as polymerase chain reaction (PCR), are extensively used in many applications to detect target DNA because of their high sensitivity, good reproducibility, and wide dynamic range of quantification. However, analytical quality control when detecting low copy number target DNA is often missing because of a lack of appropriate reference materials. Recent advances in analytical sciences require a method to accurately quantify DNA at the single molecule level.

Chimeric antibodies.

Here we describe a detailed protocol for the one-step preparation of antigen-specific human chimeric immunoglobulin G (IgG) monoclonal antibodies (mAbs) using an in vitro antibody design method referred to as the ADLib (Autonomously Diversifying Library) system. This method employs a chicken B cell line DT40-based library in which the variable regions of the Ig gene loci have been highly diversified by treatment with the histone deacetylase inhibitors. DT40 cells express both membrane-bound and secreted forms of chicken IgM.

Role of α7-nicotinic acetylcholine receptor in normal and cancer stem cells.

The α7-nicotinic acetylcholine receptor (α7-nAChR) is widely known as a neurotransmitter receptor in nervous systems. α7-nAChR is also present in a variety of non-neuronal tissues, where it has been implicated in the regulation of essential cellular functions including proliferation, survival, differentiation and communication. We have recently found in breast cancer that α7-nAChR is involved in the proliferation of cancer stem cells, which constitute a minor subpopulation responsible for tumor development and metastasis.

B-cell display-based one-step method to generate chimeric human IgG monoclonal antibodies.

The recent development of screening strategies based on the generation and display of large libraries of antibody fragments has allowed considerable advances for the in vitro isolation of monoclonal antibodies (mAbs). We previously developed a technology referred to as the 'ADLib (Autonomously Diversifying Library) system', which allows the rapid screening and isolation in vitro of antigen-specific monoclonal antibodies (mAbs) from libraries of immunoglobulin M (IgM) displayed by the chicken B-cell line DT40. Here, we report a novel application of the ADLib system to the production of chimeric human mAbs.

Distinct roles of HDAC1 and HDAC2 in transcription and recombination at the immunoglobulin loci in the chicken B cell line DT40.

The class I histone deacetylases HDAC1 and HDAC2 are highly conserved except for their C-terminal domain, but are presumed to have distinct functions in various tissues. We investigated the division of roles between HDAC1 and HDAC2 for the control of transcription and recombination at the immunoglobulin (Ig) gene in DT40. HDAC1(-/-) knock-out cells showed an increased incidence of gene conversion and of deletion/insertion events at the Ig light chain locus (IgL), but not at the heavy chain locus (IgH).

Histone H3 lysine 4 trimethylation marks meiotic recombination initiation sites.

The function of histone modifications in initiating and regulating the chromosomal events of the meiotic prophase remains poorly understood. In Saccharomyces cerevisiae, we examined the genome-wide localization of histone H3 lysine 4 trimethylation (H3K4me3) along meiosis and its relationship to gene expression and position of the programmed double-strand breaks (DSBs) that initiate interhomologue recombination, essential to yield viable haploid gametes. We find that the level of H3K4me3 is constitutively higher close to DSB sites, independently of local gene expression levels.

Modulation of immunoglobulin gene conversion frequency and distribution by the histone deacetylase HDAC2 in chicken DT40.

Modifications of histones are reportedly associated with the regulation of immunoglobulin (Ig) gene diversification mechanisms, but the extent of their involvement in promoting sequence alterations at the Ig variable (V) regions still remains to be elucidated. We have previously demonstrated that Ig gene conversion in the B cell line DT40 is accompanied by the local hyperacetylation of histones, and that its frequency is highly increased in cells treated with the histone deacetylase (HDAC) inhibitor trichostatin A (TSA). In this report, we describe the enhancing effects of the homozygous deletion of HDAC2 (HDAC2-/-) on Ig gene conversion.

Specific transcriptional responses induced by 8-methoxypsoralen and UVA in yeast.

Treatment of eukaryotic cells with 8-methoxypsoralen plus UVA irradiation (8-MOP/UVA) induces pyrimidine monoadducts and interstrand crosslinks and initiates a cascade of events leading to cytotoxic, mutagenic and carcinogenic responses. Transcriptional activation plays an important part in these responses. Our previous study in Saccharomyces cerevisiae showed that the repair of these lesions involves the transient formation of DNA double-strand breaks and the enhanced expression of landmark DNA damage response genes such as RAD51, RNR2 and DUN1, as well as the Mec1/Rad53 kinase signaling cascade.

An ex vivo method for rapid generation of monoclonal antibodies (ADLib system).

Here, we describe a protocol for using the ADLib (Autonomously Diversifying Library) system to rapidly generate specific monoclonal antibodies using DT40, a chicken B-cell line that undergoes constitutive gene conversion at both light- and heavy-chain immunoglobulin loci. We previously developed the ADLib system on the basis of our finding that gene conversion in DT40 cells was enhanced by treatment of the cells with a histone deacetylase inhibitor, trichostatin A (TSA). TSA treatment evolves a diversified library of DT40 cells (ADLib), in which each cell has different surface IgM specificity.

Set1 is required for meiotic S-phase onset, double-strand break formation and middle gene expression.

The Set1 protein of Saccharomyces cerevisiae is a histone methyltransferase (HMTase) acting on lysine 4 of histone H3. Inactivation of the SET1 gene in a diploid leads to a sporulation defect. We have studied various processes that take place during meiotic differentiation in set1delta diploid cells.

Association of Mre11p with double-strand break sites during yeast meiosis.

The repair of DNA double-strand breaks (DSBs) requires the activity of the Mre11/Rad50/Xrs2(Nbs1) complex. In Saccharomyces cerevisiae, this complex is required for both the initiation of meiotic recombination by Spo11p-catalyzed programmed DSBs and for break end resection, which is necessary for repair by homologous recombination. We report that Mre11p transiently associates with the chromatin of Spo11-dependent DSB regions throughout the genome.