SMED-TLX-1 (NR2E1) Is Critical for Tissue and Body Plan Maintenance in Schmidtea mediterranea in Fasting/Feeding Cycles
Abstract
In search for conserved members of the nuclear hormone receptors family in Schmidtea mediterranea, we identified a molecular signature of a class of NRs, NR2E1, in the Schmidtea 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.