Nuclear receptors (NRs), or nuclear hormone receptors (NHRs), are transcription factors that regulate development and metabolism of most if not all animal species. Their regulatory networks include conserved mechanisms that are shared in-between species as well as mechanisms that are restricted to certain phyla or even species. In search for conserved members of the NHR family in Schmidtea mediterranea, we identified a molecular signature of a class of NRs, NR2E1, in the S. mediterranea genome and cloned its complete cDNA coding sequence. The derived amino acid sequence shows a high degree of conservation of both DNA-binding domain and ligand- binding domain and a remarkably high homology to vertebrate NR2E1 and C. elegans NHR-67. Quantitative PCR detected approximately ten-fold higher expression of Smed-tlx-1 in the proximal part of the head compared to the tail region. The expression of Smed-tlx-1 is higher during fed state than during fasting. Smed-tlx-1 down-regulation by RNA interference affects the ability of the animals to maintain body plan and induces defects of brain, eyes and body shape during fasting and re-growing cycles. These results suggest that SMED-TLX-1 is critical for tissue and body plan maintenance in planaria.

• MeSH
• fylogeneze MeSH
• klonování DNA MeSH
• lidé MeSH
• molekulární sekvence - údaje MeSH
• omezení příjmu potravy fyziologie   MeSH
• orgánová specificita genetika   MeSH
• proteiny červů genetika   chemie   metabolismus   MeSH
• receptory cytoplazmatické a nukleární genetika   chemie   metabolismus   MeSH
• regulace genové exprese MeSH
• RNA interference MeSH
• rozvržení tělního plánu genetika   MeSH
• sekvence aminokyselin MeSH
• sekvenční seřazení MeSH
• stravovací zvyklosti fyziologie   MeSH
• Turbellaria embryologie   fyziologie   genetika   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• práce podpořená grantem MeSH

This minireview briefly surveys the complexity of regulations governing the bone metabolism. The impact of clinical studies devoted to osteoporosis is briefly summarized and the emphasis is put on the significance of experimental mouse models based on an extensive use of genetically modified animals. Despite possible arising drawbacks, the studies in mice are of prime importance for expanding our knowledge on bone metabolism. With respect to human physiology and medicine, one should be always aware of possible limitations as the experimental results may not be, or may be only to some extent, transposed to humans. If applicable to humans, results obtained in mice provide new clues for assessing unforeseen treatment strategies for patients. A recent publication representing in our opinion the important breakthrough in the field of bone metabolism in mice is commented in detail. It provides an evidence that skeleton is endocrine organ that affects energy metabolism and osteocalcin, a protein specifically synthesized and secreted by osteoblasts, is a hormone involved. If confirmed by other groups and applicable to humans, this study provides the awaited connection of long duration between bone disorders on one hand and obesity and diabetes on the other.

• MeSH
• biologické modely MeSH
• energetický metabolismus MeSH
• financování organizované MeSH
• kosti a kostní tkáň metabolismus   MeSH
• lidé MeSH
• modely u zvířat MeSH
• myši MeSH
• nemoci kostí MeSH
• obezita metabolismus   MeSH
• osteoblasty metabolismus   MeSH
• osteokalcin metabolismus   MeSH
• osteoporóza metabolismus   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• přehledy MeSH