Biology subjects

Takemoto, T.

Publications and source records attributed to Takemoto, T..

3 recordsLinked to original sources

bioRxiv2024

Histone H2B isoform H2bc27 is expressed in the developing brain of mouse embryos

Histones bind directly to DNA and play a role in regulating gene expression mediated by chromatin structure. DNA sequences of these histone genes are quite similar, which has hindered individual analyses. The exact function of the 13 different isoforms of histone H2B remains unclear. In this report, a comprehensive gene expression analysis of the H2B isoforms, focusing on tissue specificity, was conducted. We generated mice lacking the H2bc27 gene, which exhibited brain-specific expression of E14.5, and proceeded to characterize the brain tissue. The phenotype of H2bc27 knockout brains was similar to that of wild-type brains, yet transcriptome analysis indicated that H2bc27 is associated with regulating the expression of several functional genes involved in mouse brain development. The methods used in this study may serve to facilitate comprehensive H2B isoform analysis.

developmental biology↗

bioRxiv2023

An inducible germ cell ablation chicken model for high-grade germline chimeras

Chicken embryos are a powerful and widely used animal model in developmental biology studies. After the development of CRISPR technology, gene-edited chickens have been generated by transferring primordial germ cells (PGCs) after genetic modifications. However, the low inheritance caused by the competition between host germ cells and the transferred ones is the most common complication and largely reduces the production efficiency in this way. Here, we generated a gene-edited chicken, in which germ cells can be ablated in a drug-dependent manner, as recipients for gene-edited PGC transfer. We used the nitroreductase/metronidazole (NTR/Mtz) system for cell ablation, in which NTR produces cytotoxic alkylating agents from administered Mtz, causing cell apoptosis. The chicken Vasa homolog (CVH) gene locus is used to drive the expression of the NTR gene in a germ cell-specific manner. In addition, a fluorescent protein gene, mCherry, was also placed in the CVH locus to visualize the PGCs. We named this system germ cell-Specific AutonoMoUs RemovAl Induction (gSAMURAI). gSAMURAI chickens will be an ideal recipient to produce offspring derived from transplanted exogenous germ cells.

bioengineering↗

bioRxiv2019

The absence of SOX2 in the anterior foregut alters the esophagus into trachea and bronchi in both epithelial and mesenchymal components

In the anterior foregut (AFG) of mouse embryos, the transcription factor SOX2 is expressed in the epithelia of the esophagus and proximal branches of respiratory organs comprising the trachea and bronchi, whereas NKX2.1 is expressed only in the epithelia of respiratory organs. Previous studies using hypomorphic Sox2 alleles have indicated that reduced SOX2 expression causes the esophageal epithelium to display some respiratory organ characteristics. In the present study, we produced mouse embryos with AFG-specific SOX2 deficiency. In the absence of SOX2 expression, a single NKX2.1-expressing epithelial tube connected the pharynx and the stomach, and a pair of bronchi developed in the middle of the tube. Expression patterns of NKX2.1 and SOX9 revealed that the anterior and posterior halves of SOX2-deficient AFG epithelial tubes assumed the characteristics of the trachea and bronchus, respectively. In addition, we found that mesenchymal tissues surrounding the SOX2-deficient NKX2.1-expressing epithelial tube changed to those surrounding the trachea and bronchi in the anterior and posterior halves, as indicated by the arrangement of smooth muscle cells and SOX9-expressing cells and by the expression of Wnt4 (esophagus specific), Tbx4 (respiratory organ specific), and Hoxb6 (distal bronchus specific). The impact of mesenchyme-derived signaling on the early stage of AFG epithelial specification has been indicated. Our study demonstrated an opposite trend where epithelial tissue specification causes concordant changes in mesenchymal tissues, indicating a reciprocity of epithelial-mesenchymal interactions.

developmental biology↗