SnoRNAs may accelerate protein synthesis for the rapid growth of the regenerating tail blastema in the lizard Podarcis muralis

Abstract

AbstractTail regeneration in lizards derives from the formation of a regenerative blastema. Numerous snoRNAs exclusively up‐regulated in the regenerating tail but absent in the scarring limb of the lizard Podarcis muralis have been detected suggesting they are key genes for regeneration. While most snord‐, snora‐ and scarna‐RNAs are activators of protein synthesis and cell proliferation (oncogenes) some may also be tumour suppressors. A tail blastema of 2–3 mm in length consists of proliferating mesenchymal cells, fibroblasts and keratinocytes with active nucleoli, rosette‐patterned ribosomes and few rough endoplasmic cisternae. In few days, the blastema grows into a new tail indicating intense protein synthesis within this short period. A quantitative RT‐PCR analysis of snord87, snord26, snord74, snora63, scarna11, U2 and U4 shows that, aside snord87, the other ncRNAs are up‐regulated, particularly, U2, U4 and scarna11. These ncRNAs might regulate the rate of production of ribosomes from the nucleolus (snora‐ and snord‐RNAs), the splicing process (snord‐ and scarna‐RNAs, U2 and U4), the speed of protein synthesis (snora‐ and snord‐RNAs) and cell proliferation in the blastema. These non‐coding‐RNAs are hypothesized to intensify the production of more functional ribosomes that accelerate the rate of protein synthesis and rapid growth of the blastema into a new tail.