Functional variants of 5S rRNA in the ribosomes of common sea urchin Paracentrotus lividus

We have previously reported a molecular and cytogenetic characterization of three different 5S rDNA clusters in the sea urchin Paracentrotus lividus; this study, performed at DNA level only, lends itself as starting point to verify that these clusters could contain transcribed genes, then, to demonstrate the presence of heterogeneity at functional RNA level, also. In the present work we report in P. lividus ribosomes the existence of several transcribed variants of the 5S rRNA and we associate all transcribed variants to the cluster to which belong.Our finding is the first demonstration of the presence of high heterogeneity in functional 5S rRNA molecules in animal ribosomes, a feature that had been considered a peculiarity of some plants.

► The presence of functional variants of 5S rRNA in Paracentrotus lividus ribosomes ► The association of 5S rRNA minor transcript to 700 bp cluster rDNA ► The presence of all variants in all stages excluding that these are oocyte-specific ► The demonstration that high heterogeneity in 5S rRNA is not peculiarity of plants