Five novel FY null alleles associated with typing discrepancies

Abstract We identified and characterized 14 extragenic mutations that suppressed the dominant egg-laying defect of certain lin-12 gain-of-function mutations. These suppressors defined seven genes: sup-l7, lag-2, sel-4, sel-5, sel-6, sel-7 and sel-8. Mutations in six of the genes are recessive suppressors, whereas the two mutations that define the seventh gene, lag-2, are semi-dominant suppressors. These suppressor mutations were able to suppress other lin-12 gain-of-function mutations. The suppressor mutations arose at a very low frequency per gene, 10-50 times below the typical loss-of-function mutation frequency. The suppressor mutations in sup1 7 and lag-2 were shown to be rare non-null alleles, and we present evidence that null mutations in these two genes cause lethality. Temperature-shift studies for two suppressor genes, sup1 7and lag-2, suggest that both genes act at approximately the same time as lin-12in specifying a cell fate. Suppressor alleles of six of these genes enhanced a temperature-sensitive loss-of-function allele of glp-1, a gene related to lin-12 in structure and function. Our analysis of these suppressors suggests that the majority of these genes are part of a shared lin-12/glp-1 signal transduction pathway, or act to regulate the expression or stability of lin-12 and glp-1.

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Molecular Characterization of Pax62Neu Through Pax610Neu: An Extension of the Pax6 Allelic Series and the Identification of Two Possible Hypomorph Alleles in the Mouse Mus musculus

Genetics ◽

10.1093/genetics/159.4.1689 ◽

2001 ◽

Vol 159 (4) ◽

pp. 1689-1700

Author(s):

Jack Favor ◽

Heiko Peters ◽

Thomas Hermann ◽

Wolfgang Schmahl ◽

Bimal Chatterjee ◽

...

Keyword(s):

Amino Acid ◽

Molecular Characterization ◽

Amino Acid Substitution ◽

Gene Dosage ◽

Three Dimensional ◽

Null Alleles ◽

Target Sequence ◽

Allelic Series ◽

Phenotypic Analysis ◽

Major Interest

Abstract Phenotype-based mutagenesis experiments will increase the mouse mutant resource, generating mutations at previously unmarked loci as well as extending the allelic series at known loci. Mapping, molecular characterization, and phenotypic analysis of nine independent Pax6 mutations of the mouse recovered in mutagenesis experiments is presented. Seven mutations result in premature termination of translation and all express phenotypes characteristic of null alleles, suggesting that Pax6 function requires all domains to be intact. Of major interest is the identification of two possible hypomorph mutations: Heterozygotes express less severe phenotypes and homozygotes develop rudimentary eyes and nasal processes and survive up to 36 hr after birth. Pax64Neu results in an amino acid substitution within the third helix of the homeodomain. Three-dimensional modeling indicates that the amino acid substitution interrupts the homeodomain recognition α-helix, which is critical for DNA binding. Whereas cooperative dimer binding of the mutant homeodomain to a paired-class DNA target sequence was eliminated, weak monomer binding was observed. Thus, a residual function of the mutated homeodomain may explain the hypomorphic nature of the Pax64Neu allele. Pax67Neu is a base pair substitution in the Kozak sequence and results in a reduced level of Pax6 translation product. The Pax64Neu and Pax67Neu alleles may be very useful for gene-dosage studies.

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Identification and Characterization of the Genes Encoding the Core Histones and Histone Variants of Neurospora crassa

Genetics ◽

10.1093/genetics/160.3.961 ◽

2002 ◽

Vol 160 (3) ◽

pp. 961-973 ◽

Cited By ~ 1

Author(s):

Shan M Hays ◽

Johanna Swanson ◽

Eric U Selker

Keyword(s):

Neurospora Crassa ◽

Histone Variants ◽

Null Alleles ◽

Histone Genes ◽

Histone H4 ◽

Coding Regions ◽

The Core ◽

Genomic Arrangement ◽

Genes Encoding ◽

Core Histones

Abstract We have identified and characterized the complete complement of genes encoding the core histones of Neurospora crassa. In addition to the previously identified pair of genes that encode histones H3 and H4 (hH3 and hH4-1), we identified a second histone H4 gene (hH4-2), a divergently transcribed pair of genes that encode H2A and H2B (hH2A and hH2B), a homolog of the F/Z family of H2A variants (hH2Az), a homolog of the H3 variant CSE4 from Saccharomyces cerevisiae (hH3v), and a highly diverged H4 variant (hH4v) not described in other species. The hH4-1 and hH4-2 genes, which are 96% identical in their coding regions and encode identical proteins, were inactivated independently. Strains with inactivating mutations in either gene were phenotypically wild type, in terms of growth rates and fertility, but the double mutants were inviable. As expected, we were unable to isolate null alleles of hH2A, hH2B, or hH3. The genomic arrangement of the histone and histone variant genes was determined. hH2Az and the hH3-hH4-1 gene pair are on LG IIR, with hH2Az centromere-proximal to hH3-hH4-1 and hH3 centromere-proximal to hH4-1. hH3v and hH4-2 are on LG IIIR with hH3v centromere-proximal to hH4-2. hH4v is on LG IVR and the hH2A-hH2B pair is located immediately right of the LG VII centromere, with hH2A centromere-proximal to hH2B. Except for the centromere-distal gene in the pairs, all of the histone genes are transcribed toward the centromere. Phylogenetic analysis of the N. crassa histone genes places them in the Euascomycota lineage. In contrast to the general case in eukaryotes, histone genes in euascomycetes are few in number and contain introns. This may be a reflection of the evolution of the RIP (repeat-induced point mutation) and MIP (methylation induced premeiotically) processes that detect sizable duplications and silence associated genes.

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A Nucleolar Protein That Affects Mating Efficiency in Saccharomyces cerevisiae by Altering the Morphological Response to Pheromone

Genetics ◽

10.1093/genetics/149.2.795 ◽

1998 ◽

Vol 149 (2) ◽

pp. 795-805

Author(s):

Jinah Kim ◽

Jeanne P Hirsch

Keyword(s):

Growth Regulation ◽

Subcellular Location ◽

Null Alleles ◽

Temperature Sensitive ◽

Gene Products ◽

Morphological Response ◽

Mating Efficiency ◽

Yeast Genes ◽

Transcriptional Induction ◽

In Cells

Abstract SSF1 and SSF2 are redundant essential yeast genes that, when overexpressed, increase the mating efficiency of cells containing a defective Ste4p Gβ subunit. To identify the precise function of these genes in mating, different responses to pheromone were assayed in cells that either lacked or overexpressed SSF gene products. Cells containing null alleles of both SSF1 and SSF2 displayed the normal transcriptional induction response to pheromone but were unable to form mating projections. Overexpression of SSF1 conferred the ability to form mating projections on cells containing a temperature-sensitive STE4 allele, but had only a small effect on transcriptional induction. SSF1 overexpression preferentially increased the mating efficiency of a strain containing a null allele of SPA2, a gene that functions specifically in cell morphology. To investigate whether Ssf1p plays a direct physical role in mating projection formation, its subcellular location was determined. An Ssf1p-GFP fusion was found to localize to the nucleolus, implying that the role of SSF gene products in projection formation is indirect. The region of Ssf1p-GFP localization in cells undergoing projection formation was larger and more diffuse, and was often present in a specific orientation with respect to the projection. Although the function of Ssf1p appears to originate in the nucleus, it is likely that it ultimately acts on one or more of the proteins that is directly involved in the morphological response to pheromone. Because many of the proteins required for projection formation during mating are also required for bud formation during vegetative growth, regulation of the activity or amount of one or more of these proteins by Ssf1p could explain its role in both mating and dividing cells.

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Alpha-1-Antitrypsin Deficiency Associated With Null Alleles

Archivos de Bronconeumología (English Edition) ◽

10.1016/j.arbr.2017.10.005 ◽

2017 ◽

Vol 53 (12) ◽

pp. 700-702

Author(s):

Juan Marco Figueira Gonçalves ◽

Francisco Martínez Bugallo ◽

Ignacio García-Talavera ◽

Jesús Rodríguez González

Keyword(s):

Null Alleles ◽

Antitrypsin Deficiency ◽

Alpha 1 Antitrypsin Deficiency ◽

Alpha 1 Antitrypsin

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SEN1, a positive effector of tRNA-splicing endonuclease in Saccharomyces cerevisiae.

Molecular and Cellular Biology ◽

10.1128/mcb.12.5.2154 ◽

1992 ◽

Vol 12 (5) ◽

pp. 2154-2164 ◽

Cited By ~ 50

Author(s):

D J DeMarini ◽

M Winey ◽

D Ursic ◽

F Webb ◽

M R Culbertson

Keyword(s):

Saccharomyces Cerevisiae ◽

Amino Acids ◽

Amino Acid ◽

Gene Product ◽

Signal Sequence ◽

Null Alleles ◽

Nucleoside Triphosphate ◽

Temperature Sensitive ◽

Yeast Saccharomyces Cerevisiae ◽

Amino Terminal

The SEN1 gene, which is essential for growth in the yeast Saccharomyces cerevisiae, is required for endonucleolytic cleavage of introns from all 10 families of precursor tRNAs. A mutation in SEN1 conferring temperature-sensitive lethality also causes in vivo accumulation of pre-tRNAs and a deficiency of in vitro endonuclease activity. Biochemical evidence suggests that the gene product may be one of several components of a nuclear-localized splicing complex. We have cloned the SEN1 gene and characterized the SEN1 mRNA, the SEN1 gene product, the temperature-sensitive sen1-1 mutation, and three SEN1 null alleles. The SEN1 gene corresponds to a 6,336-bp open reading frame coding for a 2,112-amino-acid protein (molecular mass, 239 kDa). Using antisera directed against the C-terminal end of SEN1, we detect a protein corresponding to the predicted molecular weight of SEN1. The SEN1 protein contains a leucine zipper motif, consensus elements for nucleoside triphosphate binding, and a potential nuclear localization signal sequence. The carboxy-terminal 1,214 amino acids of the SEN1 protein are essential for growth, whereas the amino-terminal 898 amino acids are dispensable. A sequence of approximately 500 amino acids located in the essential region of SEN1 has significant similarity to the yeast UPF1 gene product, which is involved in mRNA turnover, and the mouse Mov-10 gene product, whose function is unknown. The mutation that creates the temperature-sensitive sen1-1 allele is located within this 500-amino-acid region, and it causes a substitution for an amino acid that is conserved in all three proteins.

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Multiple paternity in Chinese alligator (Alligator sinensis) clutches during a reproductive season at Xuanzhou Nature Reserve

Amphibia-Reptilia ◽

10.1163/156853810791769446 ◽

2010 ◽

Vol 31 (3) ◽

pp. 419-424 ◽

Cited By ~ 9

Author(s):

Xiao-Bing Wu ◽

Yun Hu

Keyword(s):

Dna Markers ◽

Nature Reserve ◽

Natural Populations ◽

Multiple Paternity ◽

Reproductive Season ◽

Null Alleles ◽

Chinese Alligator ◽

Microsatellite Dna Markers ◽

Alligator Sinensis ◽

Allele Assignment

AbstractPaternity testing was determined in Chinese alligator (Alligator sinensis) clutches during a reproductive season at Xuanzhou Nature Reserve, using five microsatellite loci. DNA from ten mother and offspring clutches was analysed to identify paternal alleles. Three or four paternal alleles were observed among three of ten clutches. These clutches were sired by at least two different males. This present study confirmed the effectiveness of microsatellite DNA markers in detecting multiple paternity within natural populations of Chinese alligator. However, to reduce the confounding effects of mutations and null alleles on allele assignment and to increase power to monitor individual's genetic contribution, we need additional variable genetic markers.

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Dinucleotide microsatellites from Eucalyptus sieberi: inheritance, diversity, and improved scoring of single-base differences

Genome ◽

10.1139/g01-106 ◽

2001 ◽

Vol 44 (6) ◽

pp. 1041-1045 ◽

Cited By ~ 25

Author(s):

J C Glaubitz ◽

L C Emebiri ◽

G F Moran

Keyword(s):

Base Pair ◽

Mendelian Inheritance ◽

Null Alleles ◽

Fixation Index ◽

Eucalyptus Nitens ◽

Internal Reference ◽

Single Base ◽

Hardy Weinberg Equilibrium ◽

Single Base Pair ◽

Flanking Regions

Eight dinucleotide microsatellites were developed in Eucalyptus sieberi L. Johnson (silvertop ash), a member of the subgenus Eucalyptus. Transfer of six of these to the subgenus Symphyomyrtus and their Mendelian inheritance are demonstrated using a full-sib cross in Eucalyptus nitens. Genetic diversity parameters are presented for the eight loci based on a sample of 100 old-growth E. sieberi trees from a single natural stand. One locus, Es266, had an atypically high fixation index, and significantly deviated from Hardy-Weinberg equilibrium genotypic proportions, indicating the likely presence of null alleles. Two of the loci, Es076 and Es140, had many alleles that differed in size by only a single base pair, possibly because of short poly(A) or poly(T) stretches in their flanking regions. These two loci were by far the most polymorphic, but were difficult to score reliably on a capillary DNA sequencer. Reliability of scoring of these two one-base microsatellite loci was markedly improved by the incorporation of internal reference alleles into each sample analysed.Key words: SSRs, single base pair alleles, null alleles, internal reference alleles.

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Schizosaccharomyces pombe ras1 and byr1 are functionally related genes of the ste family that affect starvation-induced transcription of mating-type genes.

Molecular and Cellular Biology ◽

10.1128/mcb.10.2.549 ◽

1990 ◽

Vol 10 (2) ◽

pp. 549-560 ◽

Cited By ~ 43

Author(s):

S A Nadin-Davis ◽

A Nasim

Keyword(s):

Gene Family ◽

Fission Yeast ◽

Mating Type ◽

Growth Cycle ◽

Yeast Cells ◽

Null Alleles ◽

Northern Analysis ◽

Gene Transcript ◽

Type Gene

We have further investigated the function of the ras1 and byr1 genes, which were previously shown to be critical for sexual differentiation in fission yeast cells. Several physiological similarities between strains containing null alleles of these genes supports the idea that ras1 and byr1 are functionally closely related. Furthermore, we have found that byr1 is allelic to ste1, one of at least 10 genes which when mutated can cause sterility. Since ras1 had previously been found to be allelic to ste5, both ras and byr genes are now clearly shown to be a part of the ste gene family, thus confirming their close functional relationship. The observation that the mating-type loci could overcome the sporulation block of ras1 and byr1 mutant strains prompted investigation of the role of the ras-byr pathway in the induction of the mating-type gene transcripts upon nitrogen starvation. By Northern analysis of RNA preparations from strains carrying wild-type or mutant ras1 alleles and grown to different stages of the growth cycle, we have shown that ras1 plays an important role in inducing the Pi transcript of the mating-type loci and the mei3 gene transcript. These observations provide a molecular basis for the role of the ste gene family, including ras1 and byr1, in meiosis and indicate that further characterization of other ste genes would be very useful for elucidating the mechanism of ras1 function in fission yeast cells.

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