Fol. Biol. 2011, 57, 223-231
SMED-TLX-1 (NR2E1) Is Critical for Tissue and Body Plan Maintenance in Schmidtea mediterranea in Fasting/Feeding Cycles
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.
Keywords
nuclear receptor, regeneration, RNA interference, Schmidtea mediterranea, Tlx.
Funding
The work was supported by Grant No. 304/08/0970 from the Czech Science Foundation and Grant No. 0021620806 from the Ministry of Education, Youth and Sports of the Czech Republic. PY was partially supported by grant SVV262502 from Charles University in Prague.
References
Copyright
This is an open-access article distributed under the terms of the Creative Commons Attribution License.
