Development, Growth & Differentiation

Research in neuroscience has greatly benefited from the development of genetic approaches that enable lineage tracing, cell type targeting, and conditional gene regulation. Recent advances in combinatorial strategies, which integrate multiple cellular features, have significantly enhanced the spatiotemporal precision and flexibility of these manipulations. In this mini review, we introduce the concept and design of these strategies and provide a few examples of their application in genetic fate mapping, cell type targeting, and reversible conditional gene regulation...

We previously identified a Xenopus tudor domain containing 6/Xenopus tudor repeats (Xtdrd6/Xtr), that was exclusively expressed in the germ cells of adult Xenopus laevis. Western blotting showed that the XTdrd6/Xtr protein was translated in St. I/II oocytes and persisted as a maternal factor until the tailbud stage. XTdrd6/Xtr has been reported to be essential for the translation of maternal mRNA involved in oocyte meiosis. In the present study, we examined the distribution of the XTdrd6/Xtr protein during oogenesis and early development, to predict the time point of its action during development...

Abnormal expression of the transcriptional regulator and hedgehog (Hh) signaling pathway effector Gli3 is known to trigger congenital disease, most frequently affecting the central nervous system (CNS) and the limbs. Accurate delineation of the genomic cis-regulatory landscape controlling Gli3 transcription during embryonic development is critical for the interpretation of non-coding variants associated with congenital defects. Here we employed a comparative genomic analysis on fish species with a slow rate of molecular evolution to identify seven previously unknown conserved noncoding elements (CNEs) in Gli3 intronic intervals (CNE15-21)...

Neural stem cells (NSCs) are a type of multipotent stem cell that generate functional newborn neurons through a process called neurogenesis. Neurogenesis in adult brain is tightly regulated and plays a pivotal role in the maintenance of brain function. Disruption of adult neurogenesis impairs cognitive function and is correlated with numerous neurologic disorders. Deciphering the mechanism underlying adult neurogenesis not only advances our understanding of how brain functions, but also offers new insight of neurologic diseases and potentially contributes to the development of effective treatments...

With advances in high-throughput, large-scale in vivo measurement and genome modification techniques at the single-nucleotide level, there is an increasing demand for the development of new technologies for the flexible design and control of cellular systems. Computer-aided design is a powerful tool to design new cells. Whole-cell modeling aims to integrate various cellular subsystems, determine their interactions and cooperative mechanisms, and predict comprehensive cellular behaviors by computational simulations on a genome-wide scale...

Neurons born during the fetal period have extreme longevity and survive until the death of the individual because the human brain has highly limited tissue regeneration. The brain is comprised of an enormous variety of neurons each exhibiting different morphological and physiological characteristics and recent studies have further reported variations in their genome including chromosomal abnormalities, copy number variations, and single nucleotide mutations. During the early stages of brain development, the increasing number of neurons generated at high speeds has been proposed to lead to chromosomal instability...

Monoaminergic systems are conserved in vertebrates, yet they present variations in neuroanatomy, genetic components and functions across species. MonoAmine Oxidase, or MAO, is the enzyme responsible for monoamine degradation. While mammals possess two genes, MAO-A and MAO-B, fish possess one single mao gene. To study the function of MAO and monoamine homeostasis on fish brain development and physiology, here we have generated a mao knockout line in Astyanax mexicanus (surface fish), by CRISPR/Cas9 technology...

In birds, primordial germ cells (PGCs) use the bloodstream to travel to a specific region, where the cells undergo extravasation followed by intrastromal migration to the gonadal crest for further colonization. Currently, DDX4, SSEA1 and Oct4 are used to identify germ cells. Other germline cell-associated molecules are N-cadherin, GnRHR, and 3βHSD, which have been used in mice and birds during gonadal development; however, its role in early gonadogenesis in birds is poorly described. This study aimed to evaluate the differential immunodetection of N-cadherin binding molecule, Oct4 pluripotency protein, GnRHR receptor and 3βHSD enzyme in Columba livia embryos during migration colonization of PGCs in the crest...

No abstract text is available yet for this article.

No abstract text is available yet for this article.

The freshwater planarian Dugesia japonica maintains an abundant heterogeneous cell population called neoblasts, which include adult pluripotent stem cells. Thus, it is an excellent model organism for stem cell and regeneration research. Recently, many single-cell RNA sequencing (scRNA-Seq) databases of several model organisms, including other planarian species, have become publicly available; these are powerful and useful resources to search for gene expression in various tissues and cells. However, only one scRNA-Seq dataset for D...

Autism spectrum disorder (ASD) is one of the most common, heritable neuropsychiatric disorders in the world, affecting almost 1% of the population. The core symptoms used to diagnose ASD are decreased social interaction and increased repetitive behaviors. Despite the large number of affected individuals, the precise mechanisms that cause this disorder remain unclear. The identification of genes and environmental factors associated with ASD allows the study of the underlying mechanisms in animal models. Although ASD presents as a human disorder, based on recent advances in understanding their brain anatomy, physiology, behavior, and evolutionary conservation of neuronal cell types, I propose that zebrafish may provide novel insights into the etiology...

Amphibians generally have three types of pigment cells, namely melanophores (black and brown), xanthophores (yellow and red), and iridophores (iridescent). Single knockout of the tyr, slc2a7, and hps6 genes in Xenopus tropicalis results in the absence of melanophores, xanthophores, and iridophores, respectively. The generation of triple- knockout (3KO) X. tropicalis for these three genes could allow for observation of internal organs without sacrificing the animals, which would be transparent due to the absence of pigments...

Zebrafish (Danio rerio) is a well-established model for studying the nervous system. Findings in zebrafish often inform studies on human diseases of the nervous system and provide crucial insight into disease mechanisms. The functions of the nervous system often rely on communication between neurons. Signal transduction is achieved via release of signaling molecules in the form of neuropeptides or neurotransmitters at synapses. Snapshots of membrane dynamics of these processes are imaged by electron microscopy...

Xian-Yang Zhong, Tao Yu, Wa Zhong, Jie-Yao Li, Zhong-Sheng Xia, Yu-Hong Yuan, Zhong Yu, Qi-Kui Chen. Lgr5 positive stem cells sorted from small intestines of diabetic mice differentiate into higher proportion of absorptive cells and Paneth cells in vitro. Development, Growth & Differentiation 2015, 57 (6), pp. 453-465 (https://onlinelibrary.wiley.com/doi/10.1111/dgd.12226). The above article, published online on 30 June 2015 in Wiley Online Library (wileyonlinelibrary.com), has been retracted by agreement between the journal's Editor in Chief Naoto Ueno and John Wiley and Sons Australia, Ltd...

Temperature sex determination (TSD) in reptiles has been studied in order to elucidate the mechanisms by which temperature is transformed into a biological signal that determines the sex of the embryo. Temperature is thought to trigger signals that alter gene expression and hormone metabolism, that will determine the development of female or male gonads. In this review we focus on collecting and discussing important and recent information on the role of maternal steroid hormones in sex determination in oviparous reptiles such as crocodiles, turtles and lizards that possess TSD...

Planarians show outstanding regenerative ability due to the proliferation of neoblasts. Hence the method to isolate planarian neoblasts is important to understand the regeneration process. In our previous study, we reported a method to isolate planarian neoblasts of Dugesia japonica using fluorescence-activated cell sorting (FACS). However, we have not yet succeeded in cultivating these cells even under in vivo conditions after transplantation into X-ray-irradiated planarians. This suggests that dissociated cells might enter apoptotic or necrotic states in the process of fluorescent dye staining and sorting...

No abstract text is available yet for this article.

Since CRISPR-based genome editing technology works effectively in the diploid frog Xenopus tropicalis, a growing number of studies have successfully modeled human genetic diseases in this species. However, most of their targets were limited to non-syndromic diseases that exhibit abnormalities in a small fraction of tissues or organs in the body. This is likely because of the complexity of interpreting the phenotypic variations resulting from somatic mosaic mutations generated in the founder animals (crispants)...

Most metazoans have a single-copy of the T-box transcription factor gene, Brachyury. This gene is expressed in cells of the blastopore of late blastulae and the archenteron invagination region of gastrulae. It appears to be crucial for gastrulation and mesoderm differentiation of embryos. Although this expression pattern is shared by most deuterostomes, Brachyury expression has not been reported in adult stages. Here we show that Brachyury of an indirect-developer, a hemichordate acorn-worm, Ptychodera flava, is expressed not only in embryonic cells, but also in cells of the caudal tip (anus) region of adults...