temperature-dependent
Dotaz
Zobrazit nápovědu
The p53 protein plays an important role in cancer prevention. In response to stress signals, p53 controls essential cell functions by regulating expression of its target genes. Full or partial loss of the p53 function in cancer cells usually results from mutations of the p53 gene. Some of them are temperature-dependent, allowing reactivation of the p53 function in certain temperature. These mutations can alter general transactivation ability of the p53 protein or they modify its transactivation only towards specific genes. We analyzed transactivation of several target genes by 23 temperature-dependent p53 mutants and stratified them into four functional groups. Seventeen p53 mutants exhibited temperature-dependency and discriminative character in human and yeast cells. Despite the differences of yeast and human cells, they allowed similar transactivation rates to the p53 mutants, thus providing evidence that functional analysis of separated alleles in yeast is valuable tool for assessment of the human p53 status.
- MeSH
- aktivace transkripce MeSH
- lidé MeSH
- mutace MeSH
- nádorové buněčné linie MeSH
- nádorový supresorový protein p53 genetika metabolismus MeSH
- Saccharomyces cerevisiae genetika metabolismus MeSH
- stanovení celkové genové exprese MeSH
- teplota MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
The p53 protein is a sequence-specific transcription factor controlling the expression of multiple genes and protecting cells from oncogenic transformation. In many tumors, the p53 protein is completely or partially inactivated by mutations in the p53 gene. We analyzed the transactivating activity of nine human temperature-dependent (td) p53 mutants in yeast cells. Mutations in seven of them were localized in the β-sandwich-coding region of the p53 gene, eight p53 mutants were temperature-sensitive and the R283C mutant was cold-sensitive. Patterns of their transactivation abilities towards three different responsive elements, the extent of their temperature dependency as well as discriminativity, were considerably variable. Similarly, their capacity to become reactivated by amifostine varied from complete resistance to high sensitivity. Transactivation abilities and temperature dependency of six p53 td mutants were determined in transiently-transfected H1299 human cells and revealed substantial concordance between the activity patterns of the p53 mutants in yeast and human cells. We concluded that the td p53 mutants do not comprise a uniform group, therefore, the behavior of each mutant has to be tested individually.
- MeSH
- aktivace transkripce * MeSH
- amifostin farmakologie MeSH
- geny p53 * MeSH
- kvasinky genetika MeSH
- lidé MeSH
- mutace MeSH
- nádorový supresorový protein p53 genetika metabolismus MeSH
- radioprotektivní látky farmakologie MeSH
- teplota MeSH
- transformace genetická MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Although birds have genetically determined sex, the sex ratio has been reported to deviate from parity in several studies. Temperature-dependent sex determination, which is common in reptiles, is absent in birds. However, females are able to adjust their investment into eggs according to the sex of the embryo, which may cause sex-specific embryonic mortality. Incubation temperature may also cause sex-biased embryonic mortality, and it may differentially affect the phenotype of male and female hatchlings. We aimed to investigate differences between male and female Mallard embryos regarding their egg size, mortality during incubation and hatchling phenotype in relation to incubation temperature. Mallard eggs were incubated under six constant incubation temperatures (ranging from 35.0 to 38.0 °C). Hatchlings were weighed, and their morphological traits were measured. We determined the sex of hatchlings and unhatched embryos by genetic analysis and found higher male embryonic mortality at 35.5 °C (44 males vs. 28 females) and a higher proportion of female hatchlings at 38 °C (24 males vs. 38 females); however, these results were not statistically significant. Our results suggest that Mallard females do not differentiate quantitatively between sexes during egg production. Male hatchlings were significantly larger but not heavier than females. The size difference between sexes was most pronounced at temperatures around 36 °C, which is the mean temperature of naturally incubated Mallard eggs.
- MeSH
- Anseriformes embryologie fyziologie MeSH
- drůbež embryologie fyziologie MeSH
- embryonální vývoj * MeSH
- inkubátory MeSH
- poměr pohlaví * MeSH
- teplota * MeSH
- zvířata MeSH
- Check Tag
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
Raman spectroscopy is an important tool to understand the structural and molecular behaviour of the liquid crystals when they undergo through different temperatures. It also helps to understand the different phase changes of the liquid crystal material as temperature changes. In this work, the structural properties of two nematic liquid crystals having relatively high clearing temperature namely 4 butylcyclohexyl-3, 5-difluoro-4- isothiocyanato biphenyl and 4-pentylcyclohexyl-3, 5-difluoro-4-isothiocyanato biphenyl are studied. The study is done using temperature dependent Raman spectroscopy. From the studies of the two compounds it has been found that the experimental values are agree well with the various functional groups and different bond assignments recorded in literature. This agreement validates the presence of different functional groups and different stretching bonds in the two studied liquid crystal compounds. Deformations of some of the peak positions of the two liquid crystal compounds have been observed with the change in phase at different temperature. Also to understand the behaviour of the Raman peak near the clearing temperatures of the liquid crystal compounds the linewidth of the different peak values at different temperature have also been studied. From the line width study, the various phase transition temperatures of the two liquid crystalline compounds can be confirmed.
- MeSH
- bifenylové sloučeniny chemie MeSH
- kapalné krystaly * chemie MeSH
- Ramanova spektroskopie metody MeSH
- teplota MeSH
- Publikační typ
- časopisecké články MeSH
The p53 gene is often mutated during cancer development. Frequency and functional consequences of these mutations vary in different tumor types. We analysed conformation and temperature dependency of 23 partially inactivating temperature-dependent (td) p53 mutants derived from various human tumors in yeast. We found considerable differences in transactivation capabilities and discriminative character of various p53 mutants. No correlations in transactivation rates and conformations of the td p53 proteins were detected. Amifostine-induced p53 reactivation occurred only in 13 of 23 td mutants, and this effect was temperature dependent and responsive element specific. The most of the p53 mutations (10/13) reactivated by amifostine were located in the part of the p53 gene coding for hydrophobic beta-sandwich structure of the DNA-binding domain.
- MeSH
- aktivace transkripce genetika účinky léků genetika MeSH
- amifostin farmakologie MeSH
- financování organizované MeSH
- konformace proteinů účinky léků MeSH
- lidé MeSH
- nádorový supresorový protein p53 biosyntéza genetika chemie MeSH
- radioprotektivní látky farmakologie MeSH
- Saccharomyces cerevisiae - proteiny genetika účinky léků MeSH
- substituce aminokyselin genetika MeSH
- teplota MeSH
- Check Tag
- lidé MeSH
Seed germination is an important life-cycle transition because it determines subsequent plant survival and reproductive success. To detect optimal spatiotemporal conditions for germination, seeds act as sophisticated environmental sensors integrating information such as ambient temperature. Here we show that the delay of germination 1 (DOG1) gene, known for providing dormancy adaptation to distinct environments, determines the optimal temperature for seed germination. By reciprocal gene-swapping experiments between Brassicaceae species we show that the DOG1-mediated dormancy mechanism is conserved. Biomechanical analyses show that this mechanism regulates the material properties of the endosperm, a seed tissue layer acting as germination barrier to control coat dormancy. We found that DOG1 inhibits the expression of gibberellin (GA)-regulated genes encoding cell-wall remodeling proteins in a temperature-dependent manner. Furthermore we demonstrate that DOG1 causes temperature-dependent alterations in the seed GA metabolism. These alterations in hormone metabolism are brought about by the temperature-dependent differential expression of genes encoding key enzymes of the GA biosynthetic pathway. These effects of DOG1 lead to a temperature-dependent control of endosperm weakening and determine the optimal temperature for germination. The conserved DOG1-mediated coat-dormancy mechanism provides a highly adaptable temperature-sensing mechanism to control the timing of germination.
- MeSH
- Arabidopsis genetika růst a vývoj fyziologie MeSH
- biomechanika MeSH
- diploidie MeSH
- geneticky modifikované rostliny MeSH
- gibereliny metabolismus MeSH
- klíčení genetika fyziologie MeSH
- konzervovaná sekvence MeSH
- Lepidium sativum genetika růst a vývoj fyziologie MeSH
- molekulární sekvence - údaje MeSH
- mutace MeSH
- proteiny huseníčku genetika MeSH
- regulace genové exprese u rostlin MeSH
- rostlinné geny MeSH
- semena rostlinná růst a vývoj MeSH
- teplota MeSH
- vegetační klid genetika fyziologie MeSH
- vývojová regulace genové exprese MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
