scholarly journals Phenotypic and molecular analysis of a transgenic insertional allele of the mouse Fused locus.

Genetics ◽  
1995 ◽  
Vol 141 (1) ◽  
pp. 321-332 ◽  
Author(s):  
W L Perry ◽  
T J Vasicek ◽  
J J Lee ◽  
J M Rossi ◽  
L Zeng ◽  
...  
Keyword(s):  
Genetic Locus ◽  
Complementation Group ◽  
Chromosome 17 ◽  
Wild Type ◽  
Recessive Lethal ◽  
Group A ◽  
Genomic Probes ◽  
Yac Contig ◽  
Compound Heterozygotes ◽  
Transgene Insertion

Abstract Spontaneous mutations at the mouse Fused (Fu) locus cause dominant skeletal and neurological defects and recessive lethal embryonic defects including neuroectodermal abnormalities and axial duplications. Here, we describe a new allele at the Fu locus caused by a transgenic insertional mutation, H epsilon 46. Embryos homozygous for the H epsilon 46 insertion die at day 9-10 post coitum and display phenotypic defects similar to those associated with Fu alleles. The H epsilon 46 locus was cloned and shown to contain a 20-kb deletion at the site of transgene insertion with no other detectable rearrangements. Genomic probes from the H epsilon 46 locus were mapped to a genetic locus closely linked to Fu on chromosome 17 and were hybridized to a YAC contig covering the FuKi critical region. Compound heterozygotes between H epsilon 46 and FuKi were inviable and displayed abnormalities at the same stage of embryogenesis as do homozygotes for either of the two mutations, demonstrating that these two recessive lethal mutations belong to the same complementation group. A genomic probe from the wild-type H epsilon 46 locus detected a transcript that is disrupted by the transgenic insertion, representing a candidate for the wild-type allele of Fused.

scholarly journals TWO RECESSIVE SUPPRESSORS OF SACCHAROMYCES CEREVISIAE CHO1 THAT ARE UNLINKED BUT FALL IN THE SAME COMPLEMENTATION GROUP

Genetics ◽  
1985 ◽  
Vol 111 (1) ◽  
pp. 1-6
Author(s):  
Katharine D Atkinson
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Meiotic Recombination ◽  
Genetic Locus ◽  
Complementation Group ◽  
Complementation Analysis ◽  
Gene Products ◽  
Chromosome X ◽  
Recessive Mutations ◽  
Recessive Mutant ◽  
Phenotypic Reversion

ABSTRACT Phenotypic reversion of ethanolamine-requiring Saccharomyces cerevisiae cho 1 mutants is predominantly due to recessive mutations at genes unlinked to the chromosome V cho 1 locus. The recessive suppressors do not correct the primary cho 1 defect in phosphatidylserine synthesis but circumvent it with a novel endogenous supply of ethanolamine. One suppressor (eam1) was previously mapped to chromosome X, and 135 suppressor isolates were identified as eam1 alleles by complementation analysis. Additional meiotic recombination studies have identified a second genetic locus, eam2, that falls in the eam1 complementation group but maps close to the centromere of chromosome IV. Although the normal EAM1 and EAM2 alleles are fully dominant over recessive mutant alleles, their dominance fails in diploids heterozygous for defects in both genes simultaneously. The unusual complementation pattern could be explained by interaction of the gene products in formation of the same enzyme.

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 Genetic and molecular analysis of the proximal region of the mouse t-complex using new molecular probes and partial t-haplotypes.

Genetics ◽  
1990 ◽  
Vol 126 (4) ◽  
pp. 1103-1114 ◽  
Author(s):  
C A Howard ◽  
G R Gummere ◽  
M F Lyon ◽  
D Bennett ◽  
K Artzt
Keyword(s):  
Wild Mouse ◽  
Molecular Probes ◽  
Proximal Region ◽  
Chromosome 17 ◽  
Lethal Gene ◽  
Strong Linkage Disequilibrium ◽  
Wild Type ◽  
T Complex ◽  
Naturally Occurring ◽  
Normal Transmission

Abstract The t-complex is located on the proximal third of chromosome 17 in the house mouse. Naturally occurring variant forms of the t-complex, known as complete t-haplotypes, are found in wild mouse populations. The t-haplotypes contain at least four nonoverlapping inversions that suppress recombination with the wild-type chromosome, and lock into strong linkage disequilibrium loci affecting normal transmission of the chromosome, male gametogenesis and embryonic development. Partial t-haplotypes derived through rare recombination between t-haplotypes and wild-type homologs have been critical in the analysis of these properties. Utilizing two new DNA probes. Au3 and Au9, and several previously described probes, we have analyzed the genetic structure of several partial t-haplotypes that have arisen in our laboratory, as well as several wild-type chromosomes deleted for loci in this region. With this approach we have been able to further our understanding of the structural and dynamic characteristics of the proximal region of the t-complex. Specifically, we have localized the D17Tul locus as most proximal known in t-haplotypes, achieved a better structural analysis of the partial t-haplotype t6, and defined the structure and lethal gene content of partial t-haplotypes derived from the lethal tw73 haplotype.

SIAMESE, a gene controlling the endoreduplication cell cycle in Arabidopsis thaliana trichomes

Development ◽  
2000 ◽  
Vol 127 (18) ◽  
pp. 3931-3940 ◽  
Author(s):  
J.D. Walker ◽  
D.G. Oppenheimer ◽  
J. Concienne ◽  
J.C. Larkin
Keyword(s):  
Cell Cycle ◽  
Cell Differentiation ◽  
Genetic Locus ◽  
Precursor Cell ◽  
Recessive Mutation ◽  
Wild Type ◽  
Normal Morphology ◽  
Cell Divisions ◽  
Nondividing Cell ◽  
Scanning Electron

Cell differentiation is generally tightly coordinated with the cell cycle, typically resulting in a nondividing cell with a unique differentiated morphology. The unicellular trichomes of Arabidopsis are a well-established model for the study of plant cell differentiation. Here, we describe a new genetic locus, SIAMESE (SIM), required for coordinating cell division and cell differentiation during the development of Arabidopsis trichomes (epidermal hairs). A recessive mutation in the sim locus on chromosome 5 results in clusters of adjacent trichomes that appeared to be morphologically identical ‘twins’. Upon closer inspection, the sim mutant was found to produce multicellular trichomes in contrast to the unicellular trichomes produced by wild-type (WT) plants. Mutant trichomes consisting of up to 15 cells have been observed. Scanning electron microscopy of developing sim trichomes suggests that the cell divisions occur very early in the development of mutant trichomes. WT trichome nuclei continue to replicate their DNA after mitosis and cytokinesis have ceased, and as a consequence have a DNA content much greater than 2C. This phenomenon is known as endoreduplication. Individual nuclei of sim trichomes have a reduced level of endoreduplication relative to WT trichome nuclei. Endoreduplication is also reduced in dark-grown sim hypocotyls relative to WT, but not in light-grown hypocotyls. Double mutants of sim with either of two other mutants affecting endoreduplication, triptychon (try) and glabra3 (gl3) are consistent with a function for SIM in endoreduplication. SIM may function as a repressor of mitosis in the endoreduplication cell cycle. Additionally, the relatively normal morphology of multicellular sim trichomes indicates that trichome morphogenesis can occur relatively normally even when the trichome precursor cell continues to divide. The sim mutant phenotype also has implications for the evolution of multicellular trichomes.

Developmentally controlled telomere addition in wild-type and mutant paramecia

1988 ◽  
Vol 8 (1) ◽  
pp. 251-258
Author(s):  
J D Forney ◽  
E H Blackburn
Keyword(s):  
Surface Antigen ◽  
Base Pair ◽  
Gene Locus ◽  
Gene Sequence ◽  
Genetic Locus ◽  
Single Site ◽  
Paramecium Tetraurelia ◽  
Wild Type ◽  
Telomeric Sequences ◽  
Antigen Gene

We analyzed sites of macronuclear telomere addition at a single genetic locus in Paramecium tetraurelia. We showed that in homozygous wild-type cells, differential genomic processing during macronuclear development resulted in the A surface antigen gene being located 8, 13, or 26 kilobases upstream from a macronuclear telomere. We describe variable rearrangements that occurred at the telomere 8 kilobases from the A gene. A mutant (d48) that forms a telomere near the 5' end of the A gene was also analyzed. This mutant was shown to create simple terminal deletions; telomeric repeats were added directly to the truncated wild-type A gene sequence. In both the mutant and wild-type cells, the telomeric sequences (a mixture of C4A2 and C3A3 repeats) were added to various sequences within a specific 200- to 500-base-pair region rather than to a single site. No similarities were found in the primary sequences surrounding the telomere addition sites. The mutation in d48 changed the region of telomere addition at the A gene locus; this is the first example in ciliates of a mutation that affects the site of telomere addition.

scholarly journals Protective Effects of Konjac and Inulin Extracts on Type 1 and Type 2 Diabetes

2019 ◽  
Vol 2019 ◽  
pp. 1-12
Author(s):  
Tianle Gao ◽  
Yue Jiao ◽  
Yang Liu ◽  
Tao Li ◽  
Zhiguo Wang ◽  
...  
Keyword(s):  
Type 2 Diabetes ◽  
Blood Glucose ◽  
Dose Group ◽  
Vehicle Control ◽  
Continuous Treatment ◽  
High Risk Population ◽  
Wild Type ◽  
Group A

Objective. The present study was designed to determine whether konjac and inulin extracts or their combination, konjac-inulin (KI) composition, as diet supplementary, can exert beneficial effects against type 1 diabetes and type 2 diabetes using animal models. Methods. A total of 60 diabetic (type 1) rats induced by streptozotocin (STZ) were randomly assigned to five groups: vehicle control (STZ group), KI combination at low dose group (KI-L group), KI combination at medium dose group (KI-M group), KI combination at high dose group (KI-H group), konjac extract group (konjac group), and inulin extract group (inulin group). A sham group (without STZ) was also included. Levels of blood glucose were monitored at each week. After continuous treatment of each diet for 24 days, a glucose tolerance test was performed. After 28 days of treatment, plasma biochemical indicators including glycated serum proteins, total cholesterol, and triglycerides were measured and immunohistochemistry staining of the rat pancreas was performed, to study the insulin expressions. Type 2 diabetes was developed in db/db mice. A total of 28 db/db mice were divided into 4 groups: vehicle control (db/db group), KI composition group (KI group), konjac extract group (konjac group), and inulin extract group (inulin group). A wild-type control group (wild-type group) for db/db mice was also included. Levels of blood glucose, body weight, and blood triglycerides were monitored at each week. Results. Daily use of the KI composition significantly decreased levels of blood glucose and blood triglycerides, as well as improved the insulin production in islets or reduced development of obesity in STZ-induced diabetic rats or in db/db mice. Such effects from KI composition were better than single ingredient of konjac or inulin extract. Conclusion. The results of this study suggest that daily use of KI composition has a protective role on type 1 and 2 diabetes and provided experimental basis for further development of KI composition as a food supplement for diabetic or diabetic high-risk population.

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