Null Allele/Null Phenotype

2011 ◽  
Keyword(s):  
Null Allele ◽  
Null Phenotype

Identification of a novel null allele of the KEL gene in a Korean patient with the Kell null phenotype

Transfusion ◽  
2020 ◽  
Vol 60 (8) ◽  
Author(s):  
Tae Yeul Kim ◽  
Heeyeon Kim ◽  
Yun Ji Hong ◽  
Kyoung Un Park
Keyword(s):  
Null Allele ◽  
Korean Patient ◽  
Null Phenotype

scholarly journals Suppressor Analysis of the Saccharomyces cerevisiae Gene REC104 Reveals a Genetic Interaction With REC102

Genetics ◽  
1999 ◽  
Vol 151 (4) ◽  
pp. 1261-1272 ◽  
Author(s):  
Laura Salem ◽  
Natalie Walter ◽  
Robert Malone
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Meiotic Recombination ◽  
Null Allele ◽  
Genetic Interaction ◽  
In Vitro Mutagenesis ◽  
Conditional Mutations ◽  
Suppressor Analysis

Abstract REC104 is a gene required for the initiation of meiotic recombination in Saccharomyces cerevisiae. To better understand the role of REC104 in meiosis, we used an in vitro mutagenesis technique to create a set of temperature-conditional mutations in REC104 and used one ts allele (rec104-8) in a screen for highcopy suppressors. An increased dosage of the early exchange gene REC102 was found to suppress the conditional recombinational reduction in rec104-8 as well as in several other conditional rec104 alleles. However, no suppression was observed for a null allele of REC104, indicating that the suppression by REC102 is not “bypass” suppression. Overexpression of the early meiotic genes REC114, RAD50, HOP1, and RED1 fails to suppress any of the rec104 conditional alleles, indicating that the suppression might be specific to REC102.

scholarly journals Genetic and Molecular Characterization of sting, a Gene Involved in Crystal Formation and Meiotic Drive in the Male Germ Line of Drosophila melanogaster

Genetics ◽  
1999 ◽  
Vol 151 (2) ◽  
pp. 749-760 ◽  
Author(s):  
Armin Schmidt ◽  
Gioacchino Palumbo ◽  
Maria P Bozzetti ◽  
Patrizia Tritto ◽  
Sergio Pimpinelli ◽  
...  
Keyword(s):  
Amino Acids ◽  
Drosophila Melanogaster ◽  
Null Allele ◽  
Germ Line ◽  
Meiotic Drive ◽  
P Element ◽  
Crystal Formation ◽  
Male Sterile ◽  
Male Sterile Mutation

Abstract The sting mutation, caused by a P element inserted into polytene region 32D, was isolated by a screen for male sterile insertions in Drosophila melanogaster. This sterility is correlated with the presence of crystals in spermatocytes and spermatids that are structurally indistinguishable from those produced in males carrying a deficiency of the Y-linked crystal (cry) locus. In addition, their morphology is needle-like in Ste+ flies and star-shaped in Ste flies, once again as observed in cry– males. The sti mutation leads to meiotic drive of the sex chromosomes, and the strength of the phenomenon is correlated with the copy number of the repetitive Ste locus. The same correlation is also true for the penetrance of the male sterile mutation. A presumptive sti null allele results in male sterility and lethal maternal effect. The gene was cloned and shown to code for a putative protein that is 866 amino acids long. A C-terminal domain of 82 amino acids is identified that is well conserved in proteins from different organisms. The gene is expressed only in the germline of both sexes. The interaction of sting with the Ste locus can also be demonstrated at the molecular level. While an unprocessed 8-kb Ste primary transcript is expressed in wild-type males, in X/Y homozygous sti males, as in X/Y cry– males, a 0.7-kb mRNA is produced.

scholarly journals The Putative RNA Helicase Dbp6p Functionally Interacts With Rpl3p, Nop8p and the Novel trans-acting Factor Rsa3p During Biogenesis of 60S Ribosomal Subunits in Saccharomyces cerevisiae

Genetics ◽  
2004 ◽  
Vol 166 (4) ◽  
pp. 1687-1699
Author(s):  
Jesús de la Cruz ◽  
Thierry Lacombe ◽  
Olivier Deloche ◽  
Patrick Linder ◽  
Dieter Kressler
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Ribosome Biogenesis ◽  
Null Allele ◽  
Ribosomal Subunit ◽  
Interaction Network ◽  
The Novel ◽  
Rna Helicases ◽  
Ribosomal Subunits ◽  
Synthetic Lethal ◽  
Synthetically Lethal

Abstract Ribosome biogenesis requires at least 18 putative ATP-dependent RNA helicases in Saccharomyces cerevisiae. To explore the functional environment of one of these putative RNA helicases, Dbp6p, we have performed a synthetic lethal screen with dbp6 alleles. We have previously characterized the nonessential Rsa1p, whose null allele is synthetically lethal with dbp6 alleles. Here, we report on the characterization of the four remaining synthetic lethal mutants, which reveals that Dbp6p also functionally interacts with Rpl3p, Nop8p, and the so-far-uncharacterized Rsa3p (ribosome assembly 3). The nonessential Rsa3p is a predominantly nucleolar protein required for optimal biogenesis of 60S ribosomal subunits. Both Dbp6p and Rsa3p are associated with complexes that most likely correspond to early pre-60S ribosomal particles. Moreover, Rsa3p is co-immunoprecipitated with protA-tagged Dbp6p under low salt conditions. In addition, we have established a synthetic interaction network among factors involved in different aspects of 60S-ribosomal-subunit biogenesis. This extensive genetic analysis reveals that the rsa3 null mutant displays some specificity by being synthetically lethal with dbp6 alleles and by showing some synthetic enhancement with the nop8-101 and the rsa1 null allele.

HLA‐A *11: 382N , a novel HLA‐A null allele identified by next‐generation sequencing

HLA ◽  
2021 ◽  
Author(s):  
Valery Cheranev ◽  
Maria Loginova ◽  
Tatjana Jankevic ◽  
Denis Rebrikov ◽  
Dmitriy Korostin
Keyword(s):  
Next Generation Sequencing ◽  
Null Allele ◽  
Next Generation ◽  
Generation Sequencing

Cytogenetic Investigation of the Rh(null) Phenotype

Vox Sanguinis ◽  
1974 ◽  
Vol 27 (2) ◽  
pp. 190-192
Author(s):  
W.L. Marsh ◽  
R.S.K. Chaganti ◽  
James German ◽  
S. Seidl ◽  
W. Spielmann
Keyword(s):  
Cytogenetic Investigation ◽  
Null Phenotype

scholarly journals A Novel Mutation in Cse1l Disrupts Brain and Eye Development with Specific Effects on Pax6 Expression

2021 ◽  
Vol 9 (3) ◽  
pp. 27
Author(s):  
Lauren E. Blizzard ◽  
Chelsea Menke ◽  
Shaili D. Patel ◽  
Ronald R. Waclaw ◽  
Salil A. Lachke ◽  
...  
Keyword(s):  
Neural Development ◽  
Null Allele ◽  
Eye Development ◽  
Novel Mutation ◽  
Forward Genetics ◽  
Mammalian Development ◽  
Variants Of Unknown Significance ◽  
New Genes ◽  
Conditional Allele ◽  
Sequencing Studies

Forward genetics in the mouse continues to be a useful and unbiased approach to identifying new genes and alleles with previously unappreciated roles in mammalian development and disease. Here, we report a new mouse allele of Cse1l that was recovered from an ENU mutagenesis screen. Embryos homozygous for the anteater allele of Cse1l display a number of variable phenotypes, with craniofacial and ocular malformations being the most obvious. We provide evidence that Cse1l is the causal gene through complementation with a novel null allele of Cse1l generated by CRISPR-Cas9 editing. While the variability in the anteater phenotype was high enough to preclude a detailed molecular analysis, we demonstrate a very penetrant reduction in Pax6 levels in the developing eye along with significant ocular developmental phenotypes. The eye gene discovery tool iSyTE shows Cse1l to be significantly expressed in the lens from early eye development stages in embryos through adulthood. Cse1l has not previously been shown to be required for organogenesis as homozygosity for a null allele results in very early lethality. Future detailed studies of Cse1l function in craniofacial and neural development will be best served with a conditional allele to circumvent the variable phenotypes we report here. We suggest that human next-generation (whole genome or exome) sequencing studies yielding variants of unknown significance in CSE1L could consider these findings as part of variant analysis.

scholarly journals Diagnosis of α-1-Antitrypsin Deficiency: An Algorithm of Quantification, Genotyping, and Phenotyping

2006 ◽  
Vol 52 (12) ◽  
pp. 2236-2242 ◽  
Author(s):  
Melissa R Snyder ◽  
Jerry A Katzmann ◽  
Malinda L Butz ◽  
Ping Yang ◽  
D Brian Dawson ◽  
...  
Keyword(s):  
Laboratory Testing ◽  
Null Allele ◽  
Melting Curve ◽  
Curve Analysis ◽  
Laboratory Evaluation ◽  
Melting Curve Analysis ◽  
Genotype Assay ◽  
Antitrypsin Deficiency ◽  
Phenotype Analysis ◽  
A1at Deficiency

Abstract Background: Laboratory testing in suspected α-1-antitrypsin (A1AT) deficiency involves analysis of A1AT concentrations and identification of specific alleles by genotyping or phenotyping. The purpose of this study was to define and evaluate a strategy that provides reliable laboratory evaluation of A1AT deficiency. Methods: Samples from 512 individuals referred for A1AT phenotype analysis were analyzed by quantification, phenotype, and genotype. A1AT concentrations were measured by nephelometry. Phenotype analysis was performed by isoelectric focusing electrophoresis. The genotype assay detected the S and Z deficiency alleles by a melting curve analysis. Results: Of the 512 samples analyzed, 2% of the phenotype and genotype results were discordant. Among these 10 discordant results, 7 were attributed to phenotyping errors. On the basis of these data we formulated an algorithm, according to which we analyzed samples by genotyping and quantification assays, with a reflex to phenotyping when the genotype and quantification results were not concordant. Retrospective analyses demonstrated that 4% of samples submitted for genotype and quantitative analysis were reflexed to phenotyping. Of the reflexed samples, phenotyping confirmed the genotype result in 85% of cases. In the remaining 15%, phenotyping provided further information, including identifying rare deficiency alleles and suggesting the presence of a null allele, and allowed for a more definitive interpretation of the genotype result. Conclusions: The combination of genotyping and quantification, with a reflex to phenotyping, is the optimal strategy for the laboratory evaluation of A1AT deficiency.

scholarly journals Molecular Basis of the Kell-null Phenotype

2000 ◽  
Vol 276 (13) ◽  
pp. 10247-10252 ◽  
Author(s):  
Lung-Chih Yu ◽  
Yuh-Ching Twu ◽  
Ching-Yi Chang ◽  
Marie Lin
Keyword(s):  
Molecular Basis ◽  
Null Phenotype
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