Search results for "mutation."
showing 10 items of 2808 documents
Inhalable nano into micro dry powders for ivacaftor delivery: The role of mannitol and cysteamine as mucus-active agents.
2020
In this paper the innovative approach of Nano into micro (NiM9 was developed to produce Nanoparticles loaded Ivacaftor to incorporate into mannitol or mannitol/cysteamine micromatrices for drug pulmonary administration in CF. Nanoparticles composed by a mixture of two polyhydrohydroxyethtylaspartamide copolymers containing a loading of Ivacaftor of 15.5 % w/w were produced. These Nanoparticles were incorporated into microparticles to obtain NiM that were characterized in terms of size and size distribution, interaction with CF-AM by rheological and turbidimetric studies as well as by aerodynamic diameter measurements. Finally the activity of Ivacaftor into these NiM was evaluated by in vitr…
Bleomycin genotoxicity alteration by glutathione and cytochrome P-450 cellular content in respiratory proficient and deficient strains of Saccharomyc…
1999
The genotoxic effects of the antiblastic drug bleomycin were studied in the D7 strain of Saccharomyces cerevisiae and on its derivative mitochondrial mutant rho degree at different cellular concentrations of two drug metabolizing systems, glutathione (GSH) and cytochrome P-450. Bleomycin mutagenic activity was evaluated as frequencies of mitotic gene conversion, reversion and total aberrations under different physiological conditions. In the D7 strain, petite mutant induction was also detected. This is important due to the role of the mitochondrial genome in cancer induction, ageing and degenerative diseases. Both strains showed higher convertant than revertant induction. At high cytochrome…
DNA binding of L1 is required for human papillomavirus morphogenesis in vivo.
2002
AbstractThe role of putative DNA-binding domains of human papillomavirus (HPV) capsid proteins for DNA encapsidation in vivo is still unknown. We have now analyzed mutants of the major capsid protein L1 of HPV type 33, which are defective for DNA binding, for their ability to encapsidate DNA using an in vivo packaging approach. Since the DNA-binding domain and the nuclear localization signal (NLS) of L1 overlap, both a carboxy-terminal deletion mutant (L1-1/470) and a substitution mutant (L1-1/477M9) were analyzed. L1-1/477M9 has the classical NLS replaced by a noncanonical NLS taken from the human hnRNP protein A1. The mutant proteins were defective for DNA binding in contrast to wild-type…
Intracellular distribution of the La antigen in CV-1 cells after herpes simplex virus type 1 infection compared with the localization of U small nucl…
1989
The La antigen is known to associate, at least transiently, with a series of small nuclear and cytoplasmic ribonucleoprotein particles (snRNPs and scRNPs), e.g. U1 and U6 snRNPs. In CV-1 cells a monoclonal antibody (MAb), directed against the La protein (La1B5), immunostained intranuclear speckles. These speckles were found to co-localize with speckles that were stained by MAbs directed against either all U snRNPs or only against U1 snRNPs. Two h after infection of CV-1 cells with herpes simplex virus type 1 (HSV-1) (strain HFEM) the staining of nuclear speckles with the anti-La MAb disappeared and the La protein was found quantitatively in the cytoplasm. In contrast nuclear speckles remain…
Identification and characterization of amphiphysin II as a novel cellular interaction partner of the hepatitis C virus NS5A protein.
2003
The hepatitis C virus (HCV) NS5A protein is highly phosphorylated by cellular protein kinases. To study how NS5A might be integrated in cellular kinase signalling, we isolated phosphoproteins from HuH-7 hepatoma cells that specifically interacted with recombinant NS5A protein. Subsequent mass spectrometry identified the adaptor protein amphiphysin II as a novel interaction partner of NS5A. Mutational analysis revealed that complex formation is primarily mediated by a proline-rich region in the C-terminal part of NS5A, which interacts with the amphiphysin II Src homology 3 domain. Importantly, we could further demonstrate specific co-precipitation and cellular co-localization of endogenous a…
The Yeast RNA Polymerase II-associated Factor Iwr1p Is Involved in the Basal and Regulated Transcription of Specific Genes
2009
RNA polymerase II (RNA pol II) is a multisubunit enzyme that requires many auxiliary factors for its activity. Over the years, these factors have been identified using both biochemical and genetic approaches. Recently, the systematic characterization of protein complexes by tandem affinity purification and mass spectroscopy has allowed the identification of new components of well established complexes, including the RNA pol II holoenzyme. Using this approach, a novel and highly conserved factor, Iwr1p, that physically interacts with most of the RNA pol II subunits has been described in yeast. Here we show that Iwr1p genetically interacts with components of the basal transcription machinery …
Cell Cycle Activation of the Swi6p Transcription Factor Is Linked to Nucleocytoplasmic Shuttling
2003
The control of the subcellular localization of cell cycle regulators has emerged as a crucial mechanism in the regulation of cell division. In the present work, we have characterized the function of the karyopherin Msn5p in the control of the cell cycle of Saccharomyces cerevisiae. Phenotypic analysis of the msn5 mutant revealed an increase in cell size and a functional interaction between Msn5p and the cell cycle transcription factor SBF (composed of the Swi4p and Swi6p proteins), indicating that Msn5p is involved in Start control. In fact, we have shown that the level of Cln2p protein is drastically reduced in an msn5 mutant. The effect on CLN2 expression is mediated at a transcriptional …
A novel regulatory mechanism of MAP kinases activation and nuclear translocation mediated by PKA and the PTP-SL tyrosine phosphatase
1999
Protein tyrosine phosphatase PTP-SL retains mitogen-activated protein (MAP) kinases in the cytoplasm in an inactive form by association through a kinase interaction motif (KIM) and tyrosine dephosphorylation. The related tyrosine phosphatases PTP-SL and STEP were phosphorylated by the cAMP-dependent protein kinase A (PKA). The PKA phosphorylation site on PTP-SL was identified as the Ser231 residue, located within the KIM. Upon phosphorylation of Ser231, PTP-SL binding and tyrosine dephosphorylation of the MAP kinases extracellular signal–regulated kinase (ERK)1/2 and p38α were impaired. Furthermore, treatment of COS-7 cells with PKA activators, or overexpression of the Cα catalytic subunit …
The sequence alteration associated with a mutational hotspot in p53 protects cells from lysis by cytotoxic T lymphocytes specific for a flanking pept…
1998
A high proportion of tumors arise due to mutation of the p53 tumor suppressor protein. A p53 hotspot mutation at amino acid position 273 from R to H, flanking a peptide epitope that spans residues 264–272, renders cells resistant to killing by human histocompatibility leukocyte antigen (HLA)-A*0201–restricted cytotoxic T lymphocytes (CTLs) specific for this epitope. Acquisition of the R to H mutation at residue 273 of the human p53 protein promotes tumor growth in vivo by selective escape from recognition by p53.264–272 peptide-specific CTLs. Synthetic 27-mer p53 polypeptides covering the antigenic nonamer region 264–272 of p53 were used as proteasome substrates to investigate whether the R…
Using Y-chromosome capture enrichment to resolve haplogroup H2 shows new evidence for a two-path Neolithic expansion to Western Europe
2021
Uniparentally-inherited markers on mitochondrial DNA (mtDNA) and the non-recombining regions of the Y chromosome (NRY), have been used for the past 30 years to investigate the history of humans from a maternal and paternal perspective. Researchers have preferred mtDNA due to its abundance in the cells, and comparatively high substitution rate. Conversely, the NRY is less susceptible to back mutations and saturation, and is potentially more informative than mtDNA owing to its longer sequence length. However, due to comparatively poor NRY coverage via shotgun sequencing, and the relatively low and biased representation of Y-chromosome variants on capture assays such as the 1240 k, ancient DNA…