Search results for "MUTATION"
showing 10 items of 2830 documents
Chromatin structure of the yeast SUC2 promoter in regulatory mutants
1992
We have previously suggested that two positioned nucleosomes are removed from the promoter of the Saccharomyces cerevisiae SUC2 gene upon derepression by glucose starvation. To gain further insight into the changes accompanying derepression at the chromatin level we have studied the chromatin structure of the SUC2 promoter in several mutants affecting SUC2 expression. The non-derepressible mutants snf1, snf2 and snf5 present a chromatin structure characteristic of the repressed state, irrespective of the presence or absence of glucose. The non-repressible mutants, mig1 and ssn6, as well as the double mutant snfs sn6 exhibit an opened chromatin structure even in the presence of glucose. Thes…
Genetic analysis of 2299delG and C759F mutations (USH2A) in patients with visual and/or auditory impairments
2004
The most common mutation in the USH2A gene (Usherin), 2299delG, causes both typical Usher (USH) syndrome type II and atypical USH syndrome, two autosomal recessive disorders, characterised by moderate to severe sensorineural hearing loss and retinitis pigmentosa (RP). Furthermore, the C759F mutation in the USH2A gene has been described in 4.5% of patients with nonsyndromic recessive RP. We have investigated the presence of the 2299delG and/or the C759F mutations in 191 unrelated Spanish patients with different syndromic and nonsyndromic retinal diseases, or with nonsyndromic hearing impairment. The 2299delG mutation was observed in patients with clinical signs of USHII or of atypical USH sy…
Epidemiological study of nonsyndromic hearing loss in Sicilian newborns
2007
Deafness is caused by a variety of facts, genetic and environmental. Regarding the acquired causes, deafness can be the consequence of prenatal infections, acoustic or cerebral trauma, and the use of ototoxic drugs. Deafness can be the only manifestation (nonsyndromic forms) or it may occur together with other phenotypic findings (syndromic forms). The majority of nonsyndromicdeafness has a genetic basis [Van Camp et al., 1997]. In recent years, deafness and hearing loss have assumed a clinical importance in the study of congenital disorders [Morton et al., 1991]. The clinical interest for hearing loss is supported by the social impact that this disorder has; if not treated, delays in the d…
Recombination in Hepatitis C Virus
2011
Hepatitis C virus (HCV) is a Flavivirus with a positive-sense, single-stranded RNA genome of about 9,600 nucleotides. It is a major cause of liver disease, infecting almost 200 million people all over the world. Similarly to most RNA viruses, HCV displays very high levels of genetic diversity which have been used to differentiate six major genotypes and about 80 subtypes. Although the different genotypes and subtypes share basic biological and pathogenic features they differ in clinical outcomes, response to treatment and epidemiology. The first HCV recombinant strain, in which different genome segments derived from parentals of different genotypes, was described in St. Petersburg (Russia) …
Human SPG11 cerebral organoids reveal cortical neurogenesis impairment
2018
Abstract Spastic paraplegia gene 11(SPG11)-linked hereditary spastic paraplegia is a complex monogenic neurodegenerative disease that in addition to spastic paraplegia is characterized by childhood onset cognitive impairment, thin corpus callosum and enlarged ventricles. We have previously shown impaired proliferation of SPG11 neural progenitor cells (NPCs). For the delineation of potential defect in SPG11 brain development we employ 2D culture systems and 3D human brain organoids derived from SPG11 patients’ iPSC and controls. We reveal that an increased rate of asymmetric divisions of NPCs leads to proliferation defect, causing premature neurogenesis. Correspondingly, SPG11 organoids appe…
Taste, movement, and death: varying effects of new prospero mutants during Drosophila development
2003
0022-3034 (Print) Comparative Study Journal Article Research Support, Non-U.S. Gov't; The PGal4 transposon inserted upstream of the pan-neural gene prospero (pros) causes several neural and behavioral defects in the Voila(1) strain. The precise excision of the transposon simultaneously rescued all these defects whereas its unprecise excision created new pros(V) alleles, including the null allele pros(V17). Here, we describe the relationship between the genetic structure of pros locus, larval locomotion, and larval gustatory response. These two behaviors showed varying degrees of variation depending upon the pros allele. We also found a good relation between behavioral alteration, the level …
Yunis-Varón Syndrome Is Caused by Mutations in FIG4, Encoding a Phosphoinositide Phosphatase
2013
Yunis-Varón syndrome (YVS) is an autosomal-recessive disorder with cleidocranial dysplasia, digital anomalies, and severe neurological involvement. Enlarged vacuoles are found in neurons, muscle, and cartilage. By whole-exome sequencing, we identified frameshift and missense mutations of FIG4 in affected individuals from three unrelated families. FIG4 encodes a phosphoinositide phosphatase required for regulation of PI(3,5)P(2) levels, and thus endosomal trafficking and autophagy. In a functional assay, both missense substitutions failed to correct the vacuolar phenotype of Fig4-null mouse fibroblasts. Homozygous Fig4-null mice exhibit features of YVS, including neurodegeneration and enlarg…
Genotyping of a nosocomial outbreak of pandemic influenza A/H1N1 2009
2011
Background: Epidemiological surveys have revealed outbreaks of pandemic influenza A (H1N1) 2009 in several different contexts. Molecular characterization of the influenza virus could help to provide a more accurate description of these outbreaks. Objective: To genotype pandemic influenza A (H1N1) 2009 isolates from an epidemiologically defined nosocomial outbreak. Study design: We sequenced the neuraminidase (NA) and hemagglutinin (HA) influenza A (H1N1) 2009 genes from ten HIV-positive patients involved in an epidemiologically defined outbreak in the Clinical Microbiology and Infectious Diseases (CMID) Department. Sequences were aligned to search for specific genetic features of the involv…
Evaluation of morphological and genetic diversity of loquat accessions grown in sicily
2015
In this study 20 accessions of loquat (Eriobotrya japonica Lindl.) that originated from Sicily and other countries were characterized phenotypically and genotyped using seven microsatellite markers. The microsatellites clearly distinguished 14 accessions; three pairs of local accessions were not differentiated, and three accessions from abroad can be considered bud sport mutations of the main Spanish cultivar âAlgerieâ. The mean alleles per locus was four, ranging from two with the marker EJ075 and five with EJ012 and EJ271; the mean Polymorphic Information Content was 0.53; the average expected and observed heterozygosities resulted 0.62 and 0.59, respectively. These values revealed a …
Analysis of S-allele genetic diversity in Sicilian almond germplasm comparing different molecular methods
2015
Italian almond germplasm is characterized by a wide diversity in several growing areas among which Sicily is one of the most important. Analysis with consensus and specific primers and DNA sequencing was performed to investigate S-RNase genetic diversity and to elucidate the homology rate within a genetic pool of 27 Italian accessions. Interestingly, some of the self-compatible cultivars did not show the presence of Sf allele. Amplicons from consensus and allele-specific PCR primers revealed a high level of variability. Sequencing of all the S-RNase amplicons derived from consensus primers allowed the identification of two new S-RNase alleles (S51 and S52). Surprisingly, despite the AA repl…