scholarly journals Triplet nucleotide removal at random positions in a target gene: the tolerance of TEM-1  -lactamase to an amino acid deletion

2005 ◽  
Vol 33 (9) ◽  
pp. e80-e80 ◽  
Author(s):  
D. D. Jones
2014 ◽  
Vol 18 (12) ◽  
pp. 1763-1770 ◽  
Author(s):  
Bernard Riss ◽  
Arnaud Grandeury ◽  
Thorsten Gut ◽  
Manuela Seeger-Weibel ◽  
Christian Zuercher ◽  
...  

Blood ◽  
1997 ◽  
Vol 90 (2) ◽  
pp. 669-677 ◽  
Author(s):  
Marie-Christine Morel-Kopp ◽  
Cécile Kaplan ◽  
Valérie Proulle ◽  
Vincent Jallu ◽  
Chantal Melchior ◽  
...  

Abstract Glanzmann's thrombasthenia (GT) is a recessive autosomal bleeding disorder characterized by abnormal platelet aggregation due to a qualitative or quantitative defect of the glycoprotein (GP) IIb-IIIa complex (integrin αIIbβ3). We describe a new mutation in the GPIIIa gene responsible for type I GT in a consanguineous Algerian family. A discordance between phenotyping and genotyping of the GPIIIa-related HPA-1 platelet alloantigen system in three family members heterozygous for the disease suggested a genetic defect in the GPIIIa gene and a normal GPIIb gene. Sequence analysis of amplified genomic DNA fragments showed a 6-bp deletion in exon 7 of the GPIIIa gene resulting in the amino acid deletion/substitution (Ile325Pro326Gly327 → Met) and creating a new BspHI restriction site. Expression of the mutated integrin β3 subunit cDNA in Chinese hamster ovary cells showed that the cDNA gene was transcribed into a full-length β3 protein with an apparent molecular weight identical to wild-type β3 and accumulated as a single-chain molecule in the cell cytoplasm. The absence of heterodimeric complex formation of the mutant β3 protein with endogeneous αv was shown by immunoprecipitation experiments, intracellular immunofluorescent labeling, and a semiquantitative enzyme-linked immunosorbent assay using the αvβ3 complex-specific monoclonal antibodies LM609 and 23C6. Substitution of the methionine residue by a proline, present at position 326 of wild-type β3, did not restore the ability of the recombinant mutant β3 protein to associate with αv, suggesting that the Ile-Pro-Gly motif is located in a β3 domain important for integrin subunit interaction. The association of a BspHI restriction site with this newly identified mutation has allowed allele-specific restriction analysis of Algerian GT individuals and the identification of two new unrelated type I patients exhibiting the same mutation, suggesting that the described mutation might be significant in this population and that BspHI restriction analysis will provide a useful screening assay for antenatal diagnosis and genetic counselling.


2003 ◽  
Vol 23 (8) ◽  
pp. 2800-2820 ◽  
Author(s):  
Mark J. Swanson ◽  
Hongfang Qiu ◽  
Laarni Sumibcay ◽  
Anna Krueger ◽  
Soon-ja Kim ◽  
...  

ABSTRACT Transcriptional activators interact with multisubunit coactivators that modify chromatin structure or recruit the general transcriptional machinery to their target genes. Budding yeast cells respond to amino acid starvation by inducing an activator of amino acid biosynthetic genes, Gcn4p. We conducted a comprehensive analysis of viable mutants affecting known coactivator subunits from the Saccharomyces Genome Deletion Project for defects in activation by Gcn4p in vivo. The results confirm previous findings that Gcn4p requires SAGA, SWI/SNF, and SRB mediator (SRB/MED) and identify key nonessential subunits of these complexes required for activation. Among the numerous histone acetyltransferases examined, only that present in SAGA, Gcn5p, was required by Gcn4p. We also uncovered a dependence on CCR4-NOT, RSC, and the Paf1 complex. In vitro binding experiments suggest that the Gcn4p activation domain interacts specifically with CCR4-NOT and RSC in addition to SAGA, SWI/SNF, and SRB/MED. Chromatin immunoprecipitation experiments show that Mbf1p, SAGA, SWI/SNF, SRB/MED, RSC, CCR4-NOT, and the Paf1 complex all are recruited by Gcn4p to one of its target genes (ARG1) in vivo. We observed considerable differences in coactivator requirements among several Gcn4p-dependent promoters; thus, only a subset of the array of coactivators that can be recruited by Gcn4p is required at a given target gene in vivo.


2010 ◽  
Vol 54 (8) ◽  
pp. 3126-3131 ◽  
Author(s):  
Shu-Hua Ge ◽  
Zhe Wan ◽  
Juan Li ◽  
Jianping Xu ◽  
Ruo-Yu Li ◽  
...  

ABSTRACT The relationship between susceptibilities to fluconazole and itraconazole and microsatellite CAI genotypes were examined from a total of 154 Candida albicans isolates (97 isolates causing vulvovaginitis in Chinese women and 6 vaginal isolates and 51 oral cavity isolates from asymptomatic carriers). The two dominant genotypes, CAI 30-45 (45 isolates) and CAI 32-46 (33 isolates), associated with vulvovaginitis showed significantly different azole susceptibility patterns with strong statistical support. CAI 32-46 isolates were usually less susceptible to both fluconazole and itraconazole than CAI 30-45 isolates and than the oral isolates with other diversified CAI genotypes. Remarkably different mutation patterns in the azole target gene ERG11 were correspondingly observed among C. albicans isolates representing different genotypes and sources. Isolates with the same or similar CAI genotypes usually possessed identical or phylogenetically closely related ERG11 sequences. Loss of heterozygosity in ERG11 was observed in all the CAI 32-46 isolates but not in the CAI 30-45 isolates and most of the oral isolates sequenced. Compared with the ERG11 sequence of strain SC5314 (X13296), two homozygous missense mutations (G487T and T916C) leading to two amino acid changes (A114S and Y257H) in Erg11p were found in CAI 32-46 isolates. The correlation between azole susceptibility and C. albicans genotype may be of potential therapeutic significance.


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