• MeSH
• fosfoproteiny fyziologie   genetika   chemie   MeSH
• tyrosinkinasy fyziologie   chemie   MeSH
• Publikační typ
• kongresy MeSH

P53 controls the growth and survival of cells by acting in response to a multitude of cellular stresses. It is, however, not yet fully understood how different p53 activation pathways result in either cell cycle arrest or apoptosis. We and others have described an N-terminally truncated p53 protein (p53/47) originating from a second translation initiation site in the p53 messenger RNA (mRNA), which can interact with p53 and impose altered stability and transactivation properties to p53 complexes. Here we show that cap-dependent and cap-independent mechanisms of initiation govern the translation of the p53 mRNA. Changes in synthesis of full-length p53 or p53/47 are regulated through distinct cell stress-induced pathways acting through separate regions of the p53 mRNA. We also show that some cytotoxic drugs require the presence of full-length p53 to induce apoptosis, whereas for others p53/47 is sufficient. This indicates that by harbouring alternative translation initiation sites, the p53 mRNA gives rise to different levels of the p53 isoforms which help to orchestrate the cell biological outcome of p53 activation in response to different types of cell stress. This sheds new light into the way p53 can integrate and differentiate a large multiplicity of changes in the cellular environment.

• MeSH
• 5' nepřekládaná oblast MeSH
• exprese genu MeSH
• lidé MeSH
• messenger RNA * metabolismus   MeSH
• nádorové buněčné linie MeSH
• nádorový supresorový protein p53 * genetika   MeSH
• northern blotting MeSH
• polymerázová řetězová reakce s reverzní transkripcí MeSH
• protein - isoformy * genetika   MeSH
• proteosyntéza * fyziologie   MeSH
• průtoková cytometrie MeSH
• regulace genové exprese * genetika   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• práce podpořená grantem MeSH

The imitation switch nuclear ATPase Smarca5 (Snf2h) is one of the most conserved chromatin remodeling factors. It exists in a variety of oligosubunit complexes that move DNA with respect to the histone octamer to generate regularly spaced nucleosomal arrays. Smarca5 interacts with different accessory proteins and represents a molecular motor for DNA replication, repair, and transcription. We deleted Smarca5 at the onset of definitive hematopoiesis (Vav1-iCre) and observed that animals die during late fetal development due to anemia. Hematopoietic stem and progenitor cells accumulated but their maturation toward erythroid and myeloid lineages was inhibited. Proerythroblasts were dysplastic while basophilic erythroblasts were blocked in G2/M and depleted. Smarca5 deficiency led to increased p53 levels, its activation at two residues, one associated with DNA damage (S15Ph°s) second with CBP/p300 (K376Ac), and finally activation of the p53 targets. We also deleted Smarca5 in committed erythroid cells (Epor-iCre) and observed that animals were anemic postnatally. Furthermore, 4-hydroxytamoxifen-mediated deletion of Smarca5 in the ex vivo cultures confirmed its requirement for erythroid cell proliferation. Thus, Smarca5 plays indispensable roles during early hematopoiesis and erythropoiesis. Stem Cells 2017;35:1614-1623.

• MeSH
• adenosintrifosfatasy nedostatek   metabolismus   MeSH
• anemie patologie   MeSH
• buněčná diferenciace * MeSH
• buněčný cyklus MeSH
• chromozomální proteiny, nehistonové nedostatek   metabolismus   MeSH
• delece genu MeSH
• erytroidní buňky cytologie   MeSH
• erytropoéza MeSH
• genotyp MeSH
• hematopoetické kmenové buňky cytologie   metabolismus   MeSH
• hematopoéza MeSH
• messenger RNA genetika   metabolismus   MeSH
• myši inbrední C57BL MeSH
• myši knockoutované MeSH
• nádorový supresorový protein p53 metabolismus   MeSH
• poškození DNA genetika   MeSH
• proliferace buněk MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, N.I.H., Extramural MeSH

Dog thyroid epithelial cells in primary culture constitute a physiologically relevant model of positive control of DNA synthesis initiation and G0-S prereplicative phase progression by cAMP as a second messenger for thyrotropin (thyroid-stimulating hormone [TSH]). As previously shown in this system, the cAMP-dependent mitogenic pathway differs from growth factor cascades as it stimulates the accumulation of p27(kip1) but not cyclins D. Nevertheless, TSH induces the nuclear translocations and assembly of cyclin D3 and cdk4, which are essential in cAMP-dependent mitogenesis. Here we demonstrate that transforming growth factor beta(1) (TGFbeta(1)) selectively inhibits the cAMP-dependent cell cycle in mid-G1 and various cell cycle regulatory events, but it weakly affects the stimulation of DNA synthesis by epidermal growth factor (EGF), hepatocyte growth factor, serum, and phorbol esters. EGF+serum and TSH did not interfere importantly with TGFbeta receptor signaling, because they did not affect the TGFbeta-induced nuclear translocation of Smad 2 and 3. TGFbeta inhibited the phosphorylation of Rb, p107, and p130 induced by TSH, but it weakly affected the phosphorylation state of Rb-related proteins in EGF+serum-treated cells. TGFbeta did not inhibit c-myc expression. In TSH-stimulated cells, TGFbeta did not affect the expression of cyclin D3, cdk4, and p27(kip1), nor the induced formation of cyclin D3-cdk4 complexes, but it prevented the TSH-induced relocalization of p27(kip1) from cdk2 to cyclin D3-cdk4. It prevented the nuclear translocations of cdk4 and cyclin D3 without altering the assembly of cyclin D3-cdk4 complexes probably formed in the cytoplasm, where they were prevented from sequestering nuclear p27(kip1) away from cdk2. This study dissociates the assembly of cyclin D3-cdk4 complexes from their nuclear localization and association with p27(kip1). It provides a new mechanism of regulation of proliferation by TGFbeta, which points out the subcellular location of cyclin D-cdk4 complexes as a crucial factor integrating mitogenic and antimitogenic regulations in an epithelial cell in primary culture.

• MeSH
• AMP cyklický * fyziologie   MeSH
• biologický transport MeSH
• buněčné dělení MeSH
• buněčný cyklus fyziologie   MeSH
• cyklin D3 MeSH
• cyklin-dependentní kinasa 2 MeSH
• cyklin-dependentní kinasa 4 MeSH
• cyklin-dependentní kinasy * metabolismus   MeSH
• cykliny * metabolismus   MeSH
• DNA vazebné proteiny metabolismus   MeSH
• epitelové buňky cytologie   MeSH
• exprese genu MeSH
• fosforylace MeSH
• inhibitor p27 cyklin-dependentní kinasy MeSH
• kinasy CDC2-CDC28 * MeSH
• kultivované buňky MeSH
• mitogeny farmakologie   MeSH
• nádorové supresorové proteiny * MeSH
• protein Smad2 MeSH
• protein Smad3 MeSH
• protein-serin-threoninkinasy MeSH
• proteiny asociované s mikrotubuly * metabolismus   MeSH
• proteiny buněčného cyklu * MeSH
• protoonkogenní proteiny c-myc biosyntéza   MeSH
• protoonkogenní proteiny * MeSH
• psi MeSH
• retinoblastomový protein metabolismus   MeSH
• štítná žláza cytologie   MeSH
• thyreotropin metabolismus   MeSH
• trans-aktivátory metabolismus   MeSH
• transformující růstový faktor beta * fyziologie   MeSH
• vazba proteinů MeSH
• zvířata MeSH
• Check Tag
• psi MeSH
• zvířata MeSH