Zebrafish as a model for studying ovarian development: Recent advances from targeted gene knockout studies.

Ovarian development is a complex process controlled by precise coordination of multiple factors. The targeted gene knockout technique is a powerful tool to study the functions of these factors. The successful application of this technique in mice in the past three decades has significantly enhanced our understanding on the molecular mechanism of ovarian development. Recently, with the advent of genome editing techniques, targeted gene knockout research can be carried out in many species. Zebrafish has emerged as an excellent model system to study the control of ovarian development. Dozens of genes related to ovarian development have been knocked out in zebrafish in recent years. Much new information and perspectives on the molecular mechanism of ovarian development have been obtained from these mutant zebrafish. Some findings have challenged conventional views. Several genes have been identified for the first time in vertebrates to control ovarian development. Focusing on ovarian development, the purpose of this review is to briefly summarize recent findings using these gene knockout zebrafish models, and compare these findings with mammalian models. These established mutants and rapid development of gene knockout techniques have prompted zebrafish as an ideal animal model for studying ovarian development.

[Progress in gene knockout mice].

The establishment and development of gene knockout mice have provided powerful support for the study of gene function and the treatment of human diseases. Gene targeting and gene trap are two techniques for generating gene knockout mice from embryonic stem cells. Gene targeting replaces endogenous knockout gene by homologous recombination. There are two ways to knock out target genes: promoter trap and polyA trap. In recent years, many new gene knockout techniques have been developed, including Cre/loxP system, CRISP/Cas9 system, latest ZFN technology and TALEN technology. This article focuses on the several new knockout mouse techniques.

Production of genome-edited pluripotent stem cells and mice by CRISPR/Cas.

Clustered regularly at interspaced short palindromic repeats (CRISPR) and CRISPR-associated (Cas) nucleases, so-called CRISPR/Cas, was recently developed as an epoch-making genome engineering technology. This system only requires Cas9 nuclease and single-guide RNA complementary to a target locus. CRISPR/Cas enables the generation of knockout cells and animals in a single step. This system can also be used to generate multiple mutations and knockin in a single step, which is not possible using other methods. In this review, we provide an overview of genome editing by CRISPR/Cas in pluripotent stem cells and mice.

Is the age of genetic surgery finally upon us?

This review discusses gene editing and its potential in oncology. Gene editing has not evolved faster towards clinical application because of its difficulty in implementation. There have been many limitations of the tools thought to be useful in therapeutic gene editing. However, recently the combinatorial use of multiple biological tools appears to have broken the barrier impending clinical development. This review gives a short primer on gene editing followed by some of the foundational work in gene editing and subsequently a discussion of programmable nucleases leading to a description of Zinc Finger Nuclease, TALENs and CRISPRs. Gene editing tools are now being used routinely to re-engineer the human genome. Theoretically, any gene or chromosomal sequence for which a targeting site can be identified could be rendered nonfunctional by the chromosomal breakage activity of Zinc Finger Nucleases, TALENs or a CRISPR/Cas9 system. Since the initial work started on the mechanism and regulation of gene editing, investigators have been searching for a way to develop these technologies as a treatment for cancer. The issue is finding a practical application of gene editing in oncology. However, progressive ideas are working their way through the research arena which may have an impact on cancer treatment.

Physiological roles of long noncoding RNAs: insight from knockout mice.

Long noncoding RNAs (lncRNAs) are a pervasive and recently recognized class of genes. lncRNAs have been proposed to modulate gene expression and nuclear architecture, but their physiological functions are still largely unclear. Several recent efforts to inactivate lncRNA genes in mouse models have shed light on their functions. Different genetic strategies have yielded specific lessons about the roles of lncRNA transcription, the lncRNA transcript itself, and underlying sequence elements. Current results indicate important functions for lncRNAs in organ development, immunity, organismal viability, and in human diseases.