Dominant Mutants of Ceruloplasmin Impair the Copper Loading Machinery in Aceruloplasminemia

Reindeer (Rd) is a dominant mutation affecting antenna morphology in the tenebrionid flour beetle, Tribolium castaneum. In contrast with most dominant mutants previously described for this species, homozygotes are fully viable, thus making Rd very useful for genetic studies. Rd is tentatively assigned to either linkage group IX or X. Abbreviated appendages (aa), formerly placed in linkage group X, is reassigned to linkage group V on the basis of demonstrated linkage to jet (j).Key words: Tribolium, mutation Rd, linkage, antenna morphology.

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Dominant mutants identify new roles for p34cdc2 in mitosis.

The EMBO Journal ◽

10.1002/j.1460-2075.1995.tb07209.x ◽

1995 ◽

Vol 14 (10) ◽

pp. 2155-2165 ◽

Cited By ~ 15

Author(s):

K. Labib ◽

R.A. Craven ◽

K. Crawford ◽

P. Nurse

Keyword(s):

Dominant Mutants

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Exploring the Structure and Function of the Mycobacterial KatG Protein Using trans-Dominant Mutants

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.47.1.188-195.2003 ◽

2003 ◽

Vol 47 (1) ◽

pp. 188-195 ◽

Cited By ~ 14

Author(s):

Joseph A. DeVito ◽

Sheldon Morris

Keyword(s):

Structure And Function ◽

Dominant Negative ◽

Dominant Negative Effect ◽

Active Site Residues ◽

Site Mutation ◽

Dominant Negative Mutation ◽

Cell Extracts ◽

Catalase Peroxidase ◽

And Function ◽

Dominant Mutants

ABSTRACT In order to probe the structure and function of the mycobacterial catalase-peroxidase enzyme (KatG), we employed a genetic approach using dominant-negative analysis of katG merodiploids. Transformation of Mycobacterium bovis BCG with various katG point mutants (expressed from low-copy-number plasmids) resulted in reductions in peroxidase and catalase activities as measured in cell extracts. These reductions in enzymatic activity usually correlated with increased resistance to the antituberculosis drug isoniazid (INH). However, for the N138S trans-dominant mutant, the catalase-peroxidase activity was significantly decreased while the sensitivity to INH was retained. trans-dominance required katG expression from multicopy plasmids and could not be demonstrated with katG mutants integrated elsewhere on the wild-type M. bovis BCG chromosome. Reversal of the mutant phenotype through plasmid exchange suggested the catalase-peroxidase deficiency occurred at the protein level and that INH resistance was not due to a second site mutation(s). Electrophoretic analysis of KatG proteins from the trans-dominant mutants showed a reduction in KatG dimers compared to WT and formation of heterodimers with reduced activity. The mutants responsible for these defects cluster around proposed active site residues: N138S, T275P, S315T, and D381G. In an attempt to identify mutants that might delimit the region(s) of KatG involved in subunit interactions, C-terminal truncations were constructed (with and without the D381G dominant-negative mutation). None of the C-terminal deletions were able to complement a ΔkatG strain, nor could they cause a dominant-negative effect on the WT. Taken together, these results suggest an intricate association between the amino- and carboxy-terminal regions of KatG and may be consistent with a domain-swapping mechanism for KatG dimer formation.

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Isolation and characterization of iron-independent positive dominant mutants of the diphtheria toxin repressor DtxR

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.95.25.14985 ◽

1998 ◽

Vol 95 (25) ◽

pp. 14985-14990 ◽

Cited By ~ 26

Author(s):

L. Sun ◽

J. vanderSpek ◽

J. R. Murphy

Keyword(s):

Diphtheria Toxin ◽

Isolation And Characterization ◽

Diphtheria Toxin Repressor ◽

Dominant Mutants

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Heat shock induced phenocopies of dominant mutants of the bithorax complex in Drosophila melanogaster

MGG Molecular & General Genetics ◽

10.1007/bf00268277 ◽

1979 ◽

Vol 172 (2) ◽

pp. 161-163 ◽

Cited By ~ 28

Author(s):

Pedro Santamaria

Keyword(s):

Drosophila Melanogaster ◽

Heat Shock ◽

Bithorax Complex ◽

Dominant Mutants

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Assembly properties of dominant and recessive mutations in the small mouse neurofilament (NF-L) subunit.

The Journal of Cell Biology ◽

10.1083/jcb.111.5.2005 ◽

1990 ◽

Vol 111 (5) ◽

pp. 2005-2019 ◽

Cited By ~ 103

Author(s):

S R Gill ◽

P C Wong ◽

M J Monteiro ◽

D W Cleveland

Keyword(s):

Amino Acids ◽

Insertional Mutagenesis ◽

Wild Type ◽

Recessive Mutations ◽

Filament Assembly ◽

Head Domain ◽

Filament Networks ◽

Carboxy Terminal ◽

Network Disruption ◽

Dominant Mutants

We have generated a set of amino- and carboxy-terminal deletions of the NF-L neurofilament gene and determined the assembly properties of the encoded subunits after coexpression with vimentin or wild-type NF-L. NF-L molecules missing greater than 30% (31 amino acids of the head) or 90% (128 amino acids of the tail) failed to incorporate into intermediate filament networks. Carboxy-terminal deletions into the rod domain yield dominant mutants that disrupt arrays assembled from wild-type subunits, even when present at levels of approximately 2% of the wild-type subunits. Even mutants retaining 55% of the tail (61 amino acids) disrupt normal arrays when accumulated above approximately 10% of wild-type subunits. Since deletion of greater than 90% of the head domain produces "recessive" assembly incompetent subunits that do not affect wild-type filament arrays, whereas smaller deletions yield efficient network disruption, we conclude that some sequence(s) in the head domain (within residues 31-87) are required for the earliest steps in filament assembly. Insertional mutagenesis in the nonhelical spacer region within the rod domain reveals that as many as eight additional amino acids can be tolerated without disrupting assembly competence.

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The Classic Lobe Eye Phenotype of Drosophila Is Caused by Transposon Insertion-Induced Misexpression of a Zinc-Finger Transcription Factor

Genetics ◽

10.1534/genetics.120.303486 ◽

2020 ◽

Vol 216 (1) ◽

pp. 117-134

Author(s):

Wonseok Son ◽

Kwang-Wook Choi

Keyword(s):

Zinc Finger ◽

Zinc Finger Protein ◽

Loss Of Function ◽

Male Recombination ◽

Link Type ◽

Transposon Insertion ◽

Eye Disc ◽

Dominant Eye ◽

Allele Specific ◽

Dominant Mutants

Drosophila Lobe (L) alleles were first discovered ∼100 years ago as spontaneous dominant mutants with characteristic developmental eye defects. However, the molecular basis for L dominant eye phenotypes has not been clearly understood. A previous work reported identification of CG10109/PRAS40 as the L gene, but subsequent analyses suggested that PRAS40 may not be related to L. Here, we revisited the L gene to clarify this discrepancy and understand the basis for the dominance of L mutations. Genetic analysis localized the L gene to Oaz, which encodes a homolog of the vertebrate zinc finger protein 423 (Zfp423) family transcriptional regulators. We demonstrate that RNAi knockdown of Oaz almost completely restores all L dominant alleles tested. Lrev6-3, a revertant allele of the L2 dominant eye phenotype, has an inframe deletion in the Oaz coding sequence. Molecular analysis of L dominant mutants identified allele-specific insertions of natural transposons (roo[ ]L1, hopper[ ]L5, and roo[ ]Lr) or alterations of a preexisting transposon (L2-specific mutations in roo[ ]Mohr) in the Oaz region. In addition, we generated additional L2-reversion alleles by CRISPR targeting at Oaz. These new loss-of-function Oaz mutations suppress the dominant L eye phenotype. Oaz protein is not expressed in wild-type eye disc but is expressed ectopically in L2/+ mutant eye disc. We induced male recombination between Oaz-GAL4 insertions and the L2 mutation through homologous recombination. By using the L2-recombined GAL4 reporters, we show that Oaz-GAL4 is expressed ectopically in L2 eye imaginal disc. Taken together, our data suggest that neomorphic L eye phenotypes are likely due to misregulation of Oaz by spontaneous transposon insertions.

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Dominant and Pharmacologically Sensitized ENU Mutagenesis Screens Uncover Novel Regulators of Hematopoiesis and Model Hematopoietic Disease.

Blood ◽

10.1182/blood.v106.11.1378.1378 ◽

2005 ◽

Vol 106 (11) ◽

pp. 1378-1378

Author(s):

William L. Stanford ◽

Nicole M. Anderson ◽

Zorana Milenkovic ◽

Lia Zitano ◽

Lee Adamson ◽

...

Keyword(s):

Gene Function ◽

Peripheral Blood ◽

Human Disease ◽

Blood Cells ◽

White Blood Cells ◽

Blood Levels ◽

Enu Mutagenesis ◽

Multiple Alleles ◽

Cell Counts ◽

Dominant Mutants

Abstract To generate new mouse models of human hematopoietic disease and increase our knowledge of the genetic networks that control hematopoiesis, we are performing dominant (generation 1 or G1) and pharmacologically-sensitized forward ethylnitrososurea (ENU) mutagenesis screens. Mice are phenotyped by saphenous vein peripheral blood analysis using an automated hematological analyzer. ENU is ideally suited to generating models of human disease and annotating gene function because the spectrum of mutations (point mutations generating leading to subtle amino acid substitutions, splicing errors, or premature termination) are similar to those often found in human disease. Furthermore, null mutations often do not represent the full extent of a gene’s function, requiring multiple alleles to fully define gene function. While dominant mutations can unequivocally cause some human diseases, often mutations in multiple genes interact and contribute to disease progression. Thus, we have developed sensitized screens that induce transient cytopenias using various pharmacological agents (5-fluorouracil, phenylhydrazine, and hydroxyurea) and analyzing the recovery in peripheral blood levels of red blood cells, white blood cells and platelets. This strategy enables identification of hematopoietic mutants that do not present abnormal blood cell counts in a homeostatic state. The induced cytopenia recovery assay is also being used as a secondary phenotyping assay for some of our G1 dominant mutants. The combined dominant and sensitized screens have yielded 14 heritable dominant mutants to date plus four additional mutants in hereditary testing. The array of mutations that we are analyzing are models for the following diseases: polycythemia, thrombocythemia, leukocytosis, anemia, and thrombocytopenia. I will discuss the progress of the mutagenesis screen and several ENU mutants, including a novel mutation in the protein tyrosine kinase Jak2, leading to thrombocythemia. This point mutation in the protein kinase domain will help us to dissect the recently discovered role of Jak2 in Myeloproliferative Diseases including Essential Thrombocythemia.

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