scholarly journals The Phloem Intercalated With Xylem-Correlated 3 Receptor-Like Kinase Constitutively Interacts With Brassinosteroid Insensitive 1-Associated Receptor Kinase 1 and Is Involved in Vascular Development in Arabidopsis

2022 ◽  
Vol 12 ◽  
Author(s):  
Ke Xu ◽  
Joris Jourquin ◽  
Maria Fransiska Njo ◽  
Long Nguyen ◽  
Tom Beeckman ◽  
...  
Keyword(s):  
Vascular Development ◽  
Receptor Kinase ◽  
Leucine Rich Repeat ◽  
Loss Of Function ◽  
Wild Type ◽  
Plant Environment ◽  
Receptor Like Kinase ◽  
Intracellular Signal ◽  
Peptide Characterization

Leucine-rich repeat receptor-like kinases (LRR-RLKs) play fundamental roles in cell-to-cell and plant-environment communication. LRR-RLKs can function as receptors perceiving endogenous or external ligands, or as coreceptors, which stabilize the complex, and enhance transduction of the intracellular signal. The LRR-RLK BAK1 is a coreceptor for different developmental and immunity pathways. In this article, we identified PXY-CORRELATED 3 (PXC3) as a BAK1-interacting LRR-RLK, which was previously reported to be transcribed in vascular tissues co-expressed with PHLOEM INTERCALATED WITH XYLEM (PXY), the receptor of the TDIF/CLE41 peptide. Characterization of pxc3 loss-of-function mutants revealed reduced hypocotyl stele width and vascular cells compared to wild type, indicating that PXC3 plays a role in the vascular development in Arabidopsis. Furthermore, our data suggest that PXC3 might function as a positive regulator of the CLE41/TDIF–TDR/PXY signaling pathway.

scholarly journals Kinetic Mechanistic Studies of Wild-Type Leucine-Rich Repeat Kinase2: Characterization of the Kinase and GTPase Activities

Biochemistry ◽  
2010 ◽  
Vol 49 (9) ◽  
pp. 2008-2017 ◽  
Author(s):  
Min Liu ◽  
Brittany Dobson ◽  
Marcie A. Glicksman ◽  
Zhenyu Yue ◽  
Ross L. Stein
Keyword(s):  
Leucine Rich Repeat ◽  
Mechanistic Studies ◽  
Wild Type

scholarly journals Characterization of an Unstable Allele of the Arabidopsis HY4 Locus

Genetics ◽  
1998 ◽  
Vol 149 (3) ◽  
pp. 1575-1585
Author(s):  
Edward P Bruggemann ◽  
Bernard Doan ◽  
Korie Handwerger ◽  
Gisela Storz
Keyword(s):  
Fast Neutron ◽  
Blue Light ◽  
Large Deletion ◽  
The Other ◽  
Epigenetic Mechanisms ◽  
Loss Of Function ◽  
Wild Type ◽  
Unusual Behavior ◽  
Recessive Lethal

Abstract The Arabidopsis HY4 gene encodes the nonessential blue light photoreceptor CRY1. Loss-of-function hy4 mutants have an elongated hypocotyl phenotype after germination under blue light. We previously analyzed 20 independent hy4 alleles produced by fast neutron mutagenesis. These alleles were grouped into two classes based on their genetic behavior and corresponding deletion size: (1) null hy4 alleles that were semidominant over wild type and contained small or moderate-sized deletions at HY4 and (2) null hy4 alleles that were recessive lethal and contained large HY4 deletions. Here we describe one additional fast neutron hy4 mutant, B144, that did not fall into either of these two classes. Mutant B144 was isolated as a heterozygote with an intermediate hy4 phenotype. One allele from this mutant, hy4-B144Δ, contains a large deletion at HY4 and is recessive lethal. The other allele from this mutant, HY4-B144*, appears to be intact and functional but is unstable and spontaneously converts to a nonfunctional hy4 allele. In addition, HY4-B144* is lethal in homozygotes and suppresses local recombination. We discuss genetic and epigenetic mechanisms that may account for the unusual behavior of the HY4-B144* allele.

scholarly journals Maximum likelihood estimation of fitness components in experimental evolution

2018 ◽  
Author(s):  
Jingxian Liu ◽  
Jackson Champer ◽  
Chen Liu ◽  
Joan Chung ◽  
Riona Reeves ◽  
...  
Keyword(s):  
Maximum Likelihood ◽  
Experimental Evolution ◽  
Evolutionary Dynamics ◽  
Likelihood Estimation ◽  
Loss Of Function ◽  
Wild Type ◽  
Fitness Components ◽  
Linked Gene ◽  
Males And Females

AbstractEstimating fitness differences between allelic variants is a central goal of experimental evolution. Current methods for inferring selection from allele frequency time series typically assume that evolutionary dynamics at the locus of interest can be described by a fixed selection coefficient. However, fitness is an aggregate of several components including mating success, fecundity, and viability, and distinguishing between these components could be critical in many scenarios. Here we develop a flexible maximum likelihood framework that can disentangle different components of fitness and estimate them individually in males and females from genotype frequency data. As a proof-of-principle, we apply our method to experimentally-evolved cage populations of Drosophila melanogaster, in which we tracked the relative frequencies of a loss-of-function and wild-type allele of yellow. This X-linked gene produces a recessive yellow phenotype when disrupted and is involved in male courtship ability. We find that the fitness costs of the yellow phenotype take the form of substantially reduced mating preference of wild-type females for yellow males, together with a modest reduction in the viability of yellow males and females. Our framework should be generally applicable to situations where it is important to quantify fitness components of specific genetic variants, including quantitative characterization of the population dynamics of CRISPR gene drives.

scholarly journals Molecular Characterization of eutF Mutants ofSalmonella typhimurium LT2 Identifies eutFLesions as Partial-Loss-of-Function tonB Alleles

1999 ◽  
Vol 181 (2) ◽  
pp. 368-374 ◽  
Author(s):  
Michael G. Thomas ◽  
George A. O’Toole ◽  
Jorge C. Escalante-Semerena
Keyword(s):  
Amino Acid ◽  
Molecular Characterization ◽  
Immunoblot Analysis ◽  
Phenotypic Characterization ◽  
Loss Of Function ◽  
Wild Type ◽  
Partial Loss ◽  
Acid Addition ◽  
Fusion Site

ABSTRACT The eutF locus of Salmonella typhimuriumLT2 was identified as a locus necessary for the utilization of ethanolamine as a sole carbon source. Initial models suggested that EutF was involved in either ethanolamine transport or was a transcriptional regulator of an ethanolamine transporter. Phenotypic characterization of eutF mutants suggested EutF was somehow involved in 1,2-propanediol, propionate, and succinate utilization. Here we provide evidence that two alleles defining the eutFlocus, Δ903 and eutF1115, are partial-loss-of-function tonB alleles. Both mutations were complemented by plasmids containing a wild-type allele of theEscherichia coli tonB gene. Immunoblot analysis using TonB monoclonal antibodies detected a TonB fusion protein in strains carrying eutF alleles. Molecular analysis of the Δ903 allele identified a deletion that resulted in the fusion of the 3′ end of tonB with the 3′ end oftrpA. In-frame translation of the tonB-trpAfusion resulted in the final 9 amino acids of TonB being replaced by a 45-amino-acid addition. We isolated a derivative of a strain carrying allele Δ903 that regained the ability to grow on ethanolamine as a carbon and energy source. The molecular characterization of the mutation that corrected the Eut−phenotype caused by allele Δ903 showed that the new mutation was a deletion of two nucleotides at the tonB-trpAfusion site. This deletion resulted in a frameshift that replaced the 45-amino-acid addition with a 5-amino-acid addition. This change resulted in a TonB protein with sufficient activity to restore growth on ethanolamine and eut operon expression to nearly wild-type levels. It was concluded that the observed EutF phenotypes were due to the partial loss of TonB function, which is proposed to result in reduced cobalamin and ferric siderophore transport in an aerobic environment; thus, the eutF locus does not exist.

scholarly journals Constitutive activation of leucine-rich repeat receptor kinase signaling pathways by BAK1-interacting receptor-like kinase 3 chimera

2020 ◽  
Author(s):  
Ulrich Hohmann ◽  
Priya Ramakrishna ◽  
Kai Wang ◽  
Laura Lorenzo-Orts ◽  
Joel Nicolet ◽  
...  
Keyword(s):  
Receptor Activation ◽  
Activation Mechanism ◽  
Signaling Proteins ◽  
Receptor Kinase ◽  
Leucine Rich Repeat ◽  
Protein Ligands ◽  
Receptor Like Kinase ◽  
Transgenic Lines ◽  
Receptor Kinase Signaling ◽  
Membrane Signaling

AbstractReceptor kinases with extracellular leucine-rich repeat domains (LRR-RKs) form the largest group of membrane signaling proteins in plants. LRR-RKs can sense small molecule, peptide or protein ligands, and may be activated by ligand-induced interaction with a shape complementary SOMATIC EMBRYOGENESIS RECEPTOR-LIKE KINASE (SERK) co-receptor kinase. We have previously shown that SERKs can also form constitutive, ligand-independent complexes with the LRR ectodomains of BAK1-interacting receptor-like kinase 3 (BIR3) receptor pseudokinases, negative regulators of LRR-RK signaling. Here we report that receptor chimaera in which the extracellular LRR domain of BIR3 is fused to the cytoplasmic kinase domains of the SERK-dependent LRR-RKs BRASSINOSTEROID INSENSITIVE1, HAESA and ERECTA form tight complexes with endogenous SERK co-receptors in the absence of ligand stimulus. Expression of these chimaera under the control of the endogenous promoter of the respective LRR-RK leads to strong gain-of-function brassinosteroid, floral abscission and stomatal patterning phenotypes, respectively. Importantly, a BIR3-GSO1/SGN3 chimera can partially complement sgn3 Casparian strip formation phenotypes, suggesting that GSO1/SGN3 receptor activation is also mediated by SERK proteins. Collectively, our protein engineering approach may be used to elucidate the physiological functions of orphan LRR-RKs and to identify their receptor activation mechanism in single transgenic lines.

scholarly journals Maximum Likelihood Estimation of Fitness Components in Experimental Evolution

Genetics ◽  
2019 ◽  
Vol 211 (3) ◽  
pp. 1005-1017 ◽  
Author(s):  
Jingxian Liu ◽  
Jackson Champer ◽  
Anna Maria Langmüller ◽  
Chen Liu ◽  
Joan Chung ◽  
...  
Keyword(s):  
Maximum Likelihood ◽  
Experimental Evolution ◽  
Likelihood Estimation ◽  
Loss Of Function ◽  
Wild Type ◽  
Fitness Components ◽  
Linked Gene ◽  
Males And Females ◽  
Gene Drives

Estimating fitness differences between allelic variants is a central goal of experimental evolution. Current methods for inferring such differences from allele frequency time series typically assume that the effects of selection can be described by a fixed selection coefficient. However, fitness is an aggregate of several components including mating success, fecundity, and viability. Distinguishing between these components could be critical in many scenarios. Here, we develop a flexible maximum likelihood framework that can disentangle different components of fitness from genotype frequency data, and estimate them individually in males and females. As a proof-of-principle, we apply our method to experimentally evolved cage populations of Drosophila melanogaster, in which we tracked the relative frequencies of a loss-of-function and wild-type allele of yellow. This X-linked gene produces a recessive yellow phenotype when disrupted and is involved in male courtship ability. We find that the fitness costs of the yellow phenotype take the form of substantially reduced mating preference of wild-type females for yellow males, together with a modest reduction in the viability of yellow males and females. Our framework should be generally applicable to situations where it is important to quantify fitness components of specific genetic variants, including quantitative characterization of the population dynamics of CRISPR gene drives.

scholarly journals Perception of a divergent family of phytocytokines by the Arabidopsis receptor kinase MIK2

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Jack Rhodes ◽  
Huanjie Yang ◽  
Steven Moussu ◽  
Freddy Boutrot ◽  
Julia Santiago ◽  
...  
Keyword(s):  
Immune Responses ◽  
Stress Responses ◽  
Multiple Roles ◽  
Receptor Kinase ◽  
Leucine Rich Repeat ◽  
Root Pathogen ◽  
Receptor Like Kinase ◽  
Receptor Kinases ◽  
Definition Of ◽  
Necessary And Sufficient

AbstractPlant genomes encode hundreds of receptor kinases and peptides, but the number of known plant receptor-ligand pairs is limited. We report that the Arabidopsis leucine-rich repeat receptor kinase LRR-RK MALE DISCOVERER 1-INTERACTING RECEPTOR LIKE KINASE 2 (MIK2) is the receptor for the SERINE RICH ENDOGENOUS PEPTIDE (SCOOP) phytocytokines. MIK2 is necessary and sufficient for immune responses triggered by multiple SCOOP peptides, suggesting that MIK2 is the receptor for this divergent family of peptides. Accordingly, the SCOOP12 peptide directly binds MIK2 and triggers complex formation between MIK2 and the BRASSINOSTEROID INSENSITIVE 1-ASSOCIATED KINASE 1 (BAK1) co-receptor. MIK2 is required for resistance to the important root pathogen Fusarium oxysporum. Notably, we reveal that Fusarium proteomes encode SCOOP-like sequences, and corresponding synthetic peptides induce MIK2-dependent immune responses. These results suggest that MIK2 may recognise Fusarium-derived SCOOP-like sequences to induce immunity against Fusarium. The definition of SCOOPs as MIK2 ligands will help to unravel the multiple roles played by MIK2 during plant growth, development and stress responses.

scholarly journals fog-2, a germ-line-specific sex determination gene required for hermaphrodite spermatogenesis in Caenorhabditis elegans.

Genetics ◽  
1988 ◽  
Vol 119 (1) ◽  
pp. 43-61 ◽  
Author(s):  
T Schedl ◽  
J Kimble
Keyword(s):  
Caenorhabditis Elegans ◽  
Sex Determination ◽  
Germ Line ◽  
Negative Regulator ◽  
Loss Of Function ◽  
Wild Type ◽  
Negative Regulators ◽  
Nematode Caenorhabditis Elegans ◽  
Isolation And Characterization

Abstract This paper describes the isolation and characterization of 16 mutations in the germ-line sex determination gene fog-2 (fog for feminization of the germ line). In the nematode Caenorhabditis elegans there are normally two sexes, self-fertilizing hermaphrodites (XX) and males (XO). Wild-type XX animals are hermaphrodite in the germ line (spermatogenesis followed by oogenesis), and female in the soma. fog-2 loss-of-function mutations transform XX animals into females while XO animals are unaffected. Thus, wild-type fog-2 is necessary for spermatogenesis in hermaphrodites but not males. The fem genes and fog-1 are each essential for specification of spermatogenesis in both XX and XO animals. fog-2 acts as a positive regulator of the fem genes and fog-1. The tra-2 and tra-3 genes act as negative regulators of the fem genes and fog-1 to allow oogenesis. Two models are discussed for how fog-2 might positively regulate the fem genes and fog-1 to permit spermatogenesis; fog-2 may act as a negative regulator of tra-2 and tra-3, or fog-2 may act positively on the fem genes and fog-1 rendering them insensitive to the negative action of tra-2 and tra-3.

scholarly journals Genetic and Functional Characterization of ANGPTL7 as a Therapeutic Target for Glaucoma

2021 ◽  
Author(s):  
Kavita Praveen ◽  
Gaurang Patel ◽  
Lauren Gurski ◽  
Ariane Ayer ◽  
Trikaladarshi Persaud ◽  
...  
Keyword(s):  
Knockout Mice ◽  
Human Genetics ◽  
Functional Characterization ◽  
Pathological Changes ◽  
Loss Of Function ◽  
Wild Type ◽  
Adult Mice ◽  
Sirna Knockdown ◽  
Coding Variants

Abstract Glaucoma is a leading cause of blindness. Current glaucoma medications work by lowering intraocular pressure (IOP), a risk factor for glaucoma, but most treatments do not directly target the pathological changes leading to increased IOP, which can manifest as medication resistance as disease progresses. To identify physiological modulators of IOP, we performed genome- and exome-wide association analysis in >129,000 individuals with IOP measurements and extended these findings to an analysis of glaucoma risk. We report the identification and functional characterization of rare coding variants (including loss-of-function variants) in ANGPTL7 associated with reduction in IOP and glaucoma protection. We validated the human genetics findings in mice by establishing that Angptl7 knockout mice have lower (~2 mmHg) basal IOP compared to wild-type, with a trend towards lower IOP also in heterozygotes. Conversely, increasing mAngptl7 levels via injection into mouse eyes increases the IOP. We also show that acute gene silencing via siRNA knockdown of Angptl7 in adult mice lowers the IOP (~2-4 mmHg), reproducing the observations in knockout mice. Collectively, our data suggest that ANGPTL7 is important for IOP homeostasis and is amenable to therapeutic modulation to help maintain a healthy IOP that can prevent onset or slow the progression of glaucoma.

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