In silico cloning and characterization of p8 homolog cDNA from common urchin (Paracentrotus lividus).

The p8 protein is a transcription factor with a basic helix-loop-helix motif and a nuclear localization signal. In the present study, a common sea urchin (Paracentrotus lividus) homolog of p8 cDNA was cloned, sequenced and characterized. The full-length p8 cDNA consists of 896 bp and encodes 71 amino acids with a molecular mass of 8.238 kD. Homology alignments found that several phosphorylation sites and the most negative (Asp and Glu)/positive (Arg) propensities charged residues were well conserved between P. lividus and other species. Analysis by RT-PCR showed that there was no obvious difference in the patterns of expression during embryogenesis from unfertilization egg up to the pluteus stage, but p8 mRNA expression levels varied among tested adult tissues suggesting that p8 has a key function in embryogenesis but non-vital function under physiological conditions. Evolution relationships between P. lividus p8 and other species p8 homologs revealed in the phylogenetic tree were in agreement with the concept of traditional taxonomy.