Chawla, A. K.; Kietrys, A. M.

RNase P, one of the earliest enzymes identified with RNA as its catalytic component, has been extensively studied across all three domains of life. In this research, we unveil circular isoforms of RNase P RNA within bacterial, fungal, and human cell lines. Comparing the bacterial variant, circM1, with its linear counterpart under diverse conditions revealed its enhanced temperature resistance and superior tolerance to Mn2+. Moreover, our findings suggest distinct protein associations for both isoforms in the presence of FBS. The human counterpart, circH1, was proved to be active in cellulo.