Genetic control of dorsal-ventral identity in the telencephalon: opposing roles for Pax6 and Gsh2

Development ◽  
2000 ◽  
Vol 127 (20) ◽  
pp. 4361-4371 ◽  
Author(s):  
H. Toresson ◽  
S.S. Potter ◽  
K. Campbell
Keyword(s):  
Cerebral Cortex ◽  
Gene Function ◽  
Abnormal Development ◽  
Loss Of Function ◽  
Embryonic Mouse ◽  
Molecular Identity ◽  
Mouse Mutants ◽  
Germinal Zone ◽  
Genetic Mechanisms ◽  
Dlx Genes

We have examined the genetic mechanisms that regulate dorsal-ventral identity in the embryonic mouse telencephalon and, in particular, the specification of progenitors in the cerebral cortex and striatum. The respective roles of Pax6 and Gsh2 in cortical and striatal development were studied in single and double loss-of-function mouse mutants. Gsh2 gene function was found to be essential to maintain the molecular identity of early striatal progenitors and in its absence the ventral telencephalic regulatory genes Mash1 and Dlx are lost from most of the striatal germinal zone. In their place, the dorsal regulators, Pax6, neurogenin 1 and neurogenin 2 are found ectopically. Conversely, Pax6 is required to maintain the correct molecular identity of cortical progenitors. In its absence, neurogenins are lost from the cortical germinal zone and Gsh2, Mash1 and Dlx genes are found ectopically. These reciprocal alterations in cortical and striatal progenitor specification lead to the abnormal development of the cortex and striatum observed in Pax6 (small eye) and Gsh2 mutants, respectively. In support of this, double homozygous mutants for Pax6 and Gsh2 exhibit significant improvements in both cortical and striatal development compared with their respective single mutants. Taken together, these results demonstrate that Pax6 and Gsh2 govern cortical and striatal development by regulating genetically opposing programs that control the expression of each other as well as the regionally expressed developmental regulators Mash1, the neurogenins and Dlx genes in telencephalic progenitors.

The LARGE2-APO1/APO2 regulatory module controls panicle size and grain number in rice

2021 ◽  
Author(s):  
Luojiang Huang ◽  
Kai Hua ◽  
Ran Xu ◽  
Dali Zeng ◽  
Ruci Wang ◽  
...  
Keyword(s):  
Agronomic Traits ◽  
Loss Of Function ◽  
Grain Number ◽  
Hect Domain ◽  
Regulatory Module ◽  
Promising Target ◽  
Meristematic Activity ◽  
Positive Regulators ◽  
Genetic Mechanisms ◽  
Biochemical Analyses

Abstract Panicle size and grain number are important agronomic traits and influence grain yield in rice (Oryza sativa), but the molecular and genetic mechanisms underlying panicle size and grain number control remain largely unknown in crops. Here we report that LARGE2 encodes a HECT-domain E3 ubiquitin ligase OsUPL2 and regulates panicle size and grain number in rice. The loss of function large2 mutants produce large panicles with increased grain number, wide grains and leaves, and thick culms. LARGE2 regulates panicle size and grain number by repressing meristematic activity. LARGE2 is highly expressed in young panicles and grains. Biochemical analyses show that LARGE2 physically associates with ABERRANT PANICLE ORGANIZATION1 (APO1) and APO2, two positive regulators of panicle size and grain number, and modulates their stabilities. Genetic analyses support that LARGE2 functions with APO1 and APO2 in a common pathway to regulate panicle size and grain number. These findings reveal a novel genetic and molecular mechanism of the LARGE2-APO1/APO2 module-mediated control of panicle size and grain number in rice, suggesting that this module is a promising target for improving panicle size and grain number in crops.

scholarly journals The Expression and Distributions of ANP32A in the Developing Brain

2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Shanshan Wang ◽  
Yunliang Wang ◽  
Qingshan Lu ◽  
Xinshan Liu ◽  
Fuyu Wang ◽  
...  
Keyword(s):  
Cerebral Cortex ◽  
Fetal Brain ◽  
Tissue Expression ◽  
Developing Brain ◽  
Adult Brain ◽  
Mammalian Brain ◽  
Dependent Manner ◽  
Growing Up ◽  
Embryonic Mouse ◽  
And Function

Acidic (leucine-rich) nuclear phosphoprotein 32 family, member A (ANP32A), has multiple functions involved in neuritogenesis, transcriptional regulation, and apoptosis. However, whether ANP32A has an effect on the mammalian developing brain is still in question. In this study, it was shown that brain was the organ that expressed the most abundant ANP32A by human multiple tissue expression (MTE) array. The distribution of ANP32A in the different adult brain areas was diverse dramatically, with high expression in cerebellum, temporal lobe, and cerebral cortex and with low expression in pons, medulla oblongata, and spinal cord. The expression of ANP32A was higher in the adult brain than in the fetal brain of not only humans but also mice in a time-dependent manner. ANP32A signals were dispersed accordantly in embryonic mouse brain. However, ANP32A was abundant in the granular layer of the cerebellum and the cerebral cortex when the mice were growing up, as well as in the Purkinje cells of the cerebellum. The variation of expression levels and distribution of ANP32A in the developing brain would imply that ANP32A may play an important role in mammalian brain development, especially in the differentiation and function of neurons in the cerebellum and the cerebral cortex.

scholarly journals Zebrafish Cre/lox regulated UFlip alleles generated by CRISPR/Cas targeted integration provide cell-type specific conditional gene inactivation

2021 ◽  
Author(s):  
Maira P. Almeida ◽  
Sekhar Kambakam ◽  
Fang Liu ◽  
Zhitao Ming ◽  
Jordan M. Welker ◽  
...  
Keyword(s):  
Gene Function ◽  
Cre Recombinase ◽  
Gene Trap ◽  
Gene Inactivation ◽  
Loss Of Function ◽  
Cell Type ◽  
Active Gene ◽  
Indel Mutation ◽  
Targeted Integration ◽  
Cell Type Specific

The ability to regulate gene activity spatially and temporally is essential to investigate cell type specific gene function during development and in postembryonic processes and disease models. The Cre/lox system has been widely used for performing cell and tissue-specific conditional analysis of gene function in zebrafish, but simple and efficient methods for isolation of stable, Cre/lox regulated alleles are lacking. Here we applied our GeneWeld CRISPR/Cas9 short homology-directed targeted integration strategy to generate floxed conditional alleles that provide robust gene knockdown and strong loss of function phenotypes. A universal targeting vector, UFlip, with sites for cloning short 24-48 bp homology arms flanking a floxed mRFP gene trap plus secondary reporter cassette, was integrated into an intron in hdac1, rbbp4, and rb1. Active, gene off orientation hdac1-UFlip-Off and rb1-UFlip-Off integration alleles result in >99% reduction of gene expression in homozygotes and recapitulate known indel loss of function phenotypes. Passive, gene on orientation rbbp4-UFlip-On and rb1-UFlip-On integration alleles do not cause phenotypes in trans-heterozygous combination with an indel mutation. Cre recombinase injection leads to recombination at alternating pairs of loxP and lox2272 sites, inverting and locking the cassette into the active, gene off orientation, and the expected mutant phenotypes. In combination with our endogenous neural progenitor Cre drivers we demonstrate rbbp4-UFlip-On and rb1-UFlip-On gene inactivation phenotypes can be restricted to specific neural cell populations. Replacement of the UFlip mRFP primary reporter gene trap with a 2A-RFP in rbbp4-UFlip-Off, or 2A-KalTA4 in rb1-UFlip-Off, shows strong RFP expression in wild type or UAS:RFP injected embryos, respectively. Together these results validate a simplified approach for efficient isolation of highly mutagenic Cre/lox responsive conditional gene alleles to advance zebrafish Cre recombinase genetics.

Concerted action of twodlxparalogs in sensory placode formation

Development ◽  
2002 ◽  
Vol 129 (13) ◽  
pp. 3127-3136 ◽  
Author(s):  
Keely S. Solomon ◽  
Andreas Fritz
Keyword(s):  
Target Genes ◽  
Expression Patterns ◽  
Regulatory Control ◽  
Present Evidence ◽  
Genetic Mechanisms ◽  
Dlx Genes ◽  
Functional Reduction ◽  
Sensory Nervous System ◽  
Necessary And Sufficient ◽  
Placode Formation

Sensory placodes are ectodermal thickenings that give rise to elements of the vertebrate cranial sensory nervous system, including the inner ear and nose. Although mutations have been described in humans, mice and zebrafish that perturb ear and nose development, no mutation is known to prevent sensory placode formation. Thus, it has been postulated that a functional redundancy exists in the genetic mechanisms that govern sensory placode development. We describe a zebrafish deletion mutation, b380, which results in a lack of both otic and olfactory placodes.The b380 deletion removes several known genes and expressed sequence tags, including dlx3 and dlx7, two transcription factors that share a homoeobox domain similar in sequence to the Drosophila Distal-less gene. dlx3 and dlx7 are expressed in an overlapping pattern in the regions that produce the otic and olfactory placodes in zebrafish. We present evidence suggesting that it is specifically the removal of these two genes that leads to the otic and olfactory phenotype of b380 mutants. Using morpholinos, antisense oligonucleotides that effectively block translation of target genes, we find that functional reduction of both dlx genes contributes to placode loss. Expression patterns of the otic marker pax2.1, olfactory marker anxV and eya1, a marker of both placodes, in morpholino-injected embryos recapitulate the reduced expression of these genes seen in b380 mutants. We also examine expression of dlx3 and dlx7 in the morpholino-injected embryos and present evidence for existence of auto- and cross-regulatory control of expression among these genes.We demonstrate that dlx3 is necessary and sufficient for proper otic and olfactory placode development. However, our results indicate that dlx3 and dlx7 act in concert and their importance in placode formation is only revealed by inactivating both paralogs.

The hem of the embryonic cerebral cortex is defined by the expression of multiple Wnt genes and is compromised in Gli3-deficient mice

Development ◽  
1998 ◽  
Vol 125 (12) ◽  
pp. 2315-2325 ◽  
Author(s):  
E.A. Grove ◽  
S. Tole ◽  
J. Limon ◽  
L. Yip ◽  
C.W. Ragsdale
Keyword(s):  
Gene Expression ◽  
Cerebral Cortex ◽  
Choroid Plexus ◽  
Gene Families ◽  
Cubitus Interruptus ◽  
Embryonic Mouse ◽  
Developmental Relationship ◽  
Cortical Hem ◽  
Deficient Mice

In the developing vertebrate CNS, members of the Wnt gene family are characteristically expressed at signaling centers that pattern adjacent parts of the neural tube. To identify candidate signaling centers in the telencephalon, we isolated Wnt gene fragments from cDNA derived from embryonic mouse telencephalon. In situ hybridization experiments demonstrate that one of the isolated Wnt genes, Wnt7a, is broadly expressed in the embryonic telencephalon. By contrast, three others, Wnt3a, 5a and a novel mouse Wnt gene, Wnt2b, are expressed only at the medial edge of the telencephalon, defining the hem of the cerebral cortex. The Wnt-rich cortical hem is a transient, neuron-containing, neuroepithelial structure that forms a boundary between the hippocampus and the telencephalic choroid plexus epithelium (CPe) throughout their embryonic development. Indicating a close developmental relationship between the cortical hem and the CPe, Wnt gene expression is upregulated in the cortical hem both before and just as the CPe begins to form, and persists until birth. In addition, although the cortical hem does not show features of differentiated CPe, such as expression of transthyretin mRNA, the CPe and cortical hem are linked by shared expression of members of the Bmp and Msx gene families. In the extra-toesJ (XtJ) mouse mutant, telencephalic CPe fails to develop. We show that Wnt gene expression is deficient at the cortical hem in XtJ/XtJ mice, but that the expression of other telencephalic developmental control genes, including Wnt7a, is maintained. The XtJ mutant carries a deletion in Gli3, a vertebrate homolog of the Drosophila gene cubitus interruptus (ci), which encodes a transcriptional regulator of the Drosophila Wnt gene, wingless. Our observations indicate that Gli3 participates in Wnt gene regulation in the vertebrate telencephalon, and suggest that the loss of telencephalic choroid plexus in XtJ mice is due to defects in the cortical hem that include Wnt gene misregulation.

scholarly journals Proxies of CRISPR/Cas9 Activity To Aid in the Identification of Mutagenized Arabidopsis Plants

2020 ◽  
Vol 10 (6) ◽  
pp. 2033-2042 ◽  
Author(s):  
Renyu Li ◽  
Charles Vavrik ◽  
Cristian H. Danna
Keyword(s):  
Arabidopsis Thaliana ◽  
Gene Function ◽  
Good Predictor ◽  
Gene Editing ◽  
Selection Strategy ◽  
Directed Mutagenesis ◽  
Loss Of Function ◽  
Editing Event ◽  
Endogenous Gene ◽  
Non Coding Rnas

CRISPR/Cas9 has become the preferred gene-editing technology to obtain loss-of-function mutants in plants, and hence a valuable tool to study gene function. This is mainly due to the easy reprogramming of Cas9 specificity using customizable small non-coding RNAs, and to the possibility of editing several independent genes simultaneously. Despite these advances, the identification of CRISPR-edited plants remains time and resource-intensive. Here, based on the premise that one editing event in one locus is a good predictor of editing event/s in other locus/loci, we developed a CRISPR co-editing selection strategy that greatly facilitates the identification of CRISPR-mutagenized Arabidopsis thaliana plants. This strategy is based on targeting the gene/s of interest simultaneously with a proxy of CRISPR-Cas9-directed mutagenesis. The proxy is an endogenous gene whose loss-of-function produces an easy-to-detect visible phenotype that is unrelated to the expected phenotype of the gene/s under study. We tested this strategy via assessing the frequency of co-editing of three functionally unrelated proxy genes. We found that each proxy predicted the occurrence of mutations in each surrogate gene with efficiencies ranging from 68 to 100%. The selection strategy laid out here provides a framework to facilitate the identification of multiplex edited plants, thus aiding in the study of gene function when functional redundancy hinders the effort to define gene-function-phenotype links.

Interpreting Neonatal Lethal Phenotypes in Mouse Mutants: Insights Into Gene Function and Human Diseases

2009 ◽  
Vol 89 (1) ◽  
pp. 1-26 ◽  
Author(s):  
Benjamin Turgeon ◽  
Sylvain Meloche
Keyword(s):  
Gene Function ◽  
Gene Mutations ◽  
Mutant Mice ◽  
Human Diseases ◽  
Mouse Development ◽  
Phenotypic Analysis ◽  
Mouse Mutants ◽  
Physiological Processes ◽  
Neonatal Lethality ◽  
The Impact

The mouse represents the model of choice to study the biological function of mammalian genes through mutation of its genome. However, the biggest challenge of mouse geneticists remains the phenotypic analysis of mouse mutants. A survey of mouse mutant databases reveals a surprisingly high number of gene mutations leading to neonatal death. These genetically modified mouse mutants have been instrumental in elucidating gene function and have become important models of congenital human diseases. The main complication when phenotyping mutant mice dying during the neonatal period is the large spectrum of physiological systems whose defects can challenge neonatal survival. Here, we present a comprehensive review of gene mutations leading to neonatal lethality and discuss the impact of these mutations on the major physiological processes critical to mouse newborn survival: parturition, breathing, suckling, and homeostasis. Selected examples of mouse mutants are highlighted to illustrate how the precise identification of the timing and cause of death associated with these physiological processes allows for a more profound understanding of the underlying cellular and molecular defects. This review provides a guide for the analysis of neonatal lethal phenotypes in mutant mice that will be helpful for dissecting out the function of specific genes during mouse development.

scholarly journals Loss of Wwox Causes Defective Development of Cerebral Cortex with Hypomyelination in a Rat Model of Lethal Dwarfism with Epilepsy

2019 ◽  
Vol 20 (14) ◽  
pp. 3596 ◽  
Author(s):  
Yuki Tochigi ◽  
Yutaka Takamatsu ◽  
Jun Nakane ◽  
Rika Nakai ◽  
Kentaro Katayama ◽  
...  
Keyword(s):  
Cerebral Cortex ◽  
Rat Model ◽  
Physiological Role ◽  
Early Death ◽  
Neurite Growth ◽  
Loss Of Function ◽  
Age Related ◽  
Putative Tumor Suppressor ◽  
Severe Reduction

WW domain-containing oxidoreductase (Wwox) is a putative tumor suppressor. Several germline mutations of Wwox have been associated with infant neurological disorders characterized by epilepsy, growth retardation, and early death. Less is known, however, about the pathological link between Wwox mutations and these disorders or the physiological role of Wwox in brain development. In this study, we examined age-related expression and histological localization of Wwox in forebrains as well as the effects of loss of function mutations in the Wwox gene in the immature cortex of a rat model of lethal dwarfism with epilepsy (lde/lde). Immunostaining revealed that Wwox is expressed in neurons, astrocytes, and oligodendrocytes. lde/lde cortices were characterized by a reduction in neurite growth without a reduced number of neurons, severe reduction in myelination with a reduced number of mature oligodendrocytes, and a reduction in cell populations of astrocytes and microglia. These results indicate that Wwox is essential for normal development of neurons and glial cells in the cerebral cortex.

scholarly journals Artificial Selection for Pathogenicity Mutations inStaphylococcus aureusIdentifies Novel Factors Relevant to Chronic Infection

2019 ◽  
Vol 87 (4) ◽  
Author(s):  
Kathryn McLean ◽  
Elizabeth A. Holmes ◽  
Kelsi Penewit ◽  
Duankun K. Lee ◽  
Samantha R. Hardy ◽  
...  
Keyword(s):  
Artificial Selection ◽  
Chronic Infection ◽  
Loss Of Function ◽  
Diverse Range ◽  
Content Type ◽  
Transposon Mutants ◽  
Genetic Mechanisms ◽  
Functionally Diverse ◽  
Chromosomal Mutations ◽  
Virulence Regulator

ABSTRACTAdaptation ofStaphylococcus aureusto host microenvironments during chronic infection involves spontaneous mutations, yet changes underlying adaptive phenotypes remain incompletely explored. Here, we employed artificial selection and whole-genome sequencing to better characterize spontaneous chromosomal mutations that alter two pathogenicity phenotypes relevant to chronic infection inS. aureus: intracellular invasiveness and intracellular cytotoxicity. We identified 23 genes whose alteration coincided with enhanced virulence, 11 that were previously known and 12 (52%) that had no previously described role inS. aureuspathogenicity. Using precision genome editing, transposon mutants, and gene complementation, we empirically assessed the contributions of individual genes to the two virulence phenotypes. We functionally validated 14 of 21 genes tested as measurably influencing invasion and/or cytotoxicity, including 8 newly implicated by this study. We identified inactivating mutations (murA,ndhC, and a hypothetical membrane protein) and gain-of-function mutations (aroEThr182Ile,yhcFThr74Ile, and Asp486Glu in a hypothetical peptidase) in previously unrecognizedS. aureusvirulence genes that enhance pathogenesis when introduced into a clean genetic background, as well as a novel activating mutation in the known virulence regulator genesaeS(Ala106Thr). Investigation of potentially epistatic interactions identified atufAmutation (Ala271Val) that enhances virulence only in the context of purine operon repressor gene (purR) inactivation. This project reveals a functionally diverse range of genes affected by gain- or loss-of-function mutations that contribute toS. aureusadaptive virulence phenotypes. More generally, the work establishes artificial selection as a means to determine the genetic mechanisms underlying complex bacterial phenotypes relevant to adaptation during infection.

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