Abstracts

Railroadworms luciferases from Matsinocerinae subfamily emit the widest range of bioluminescence colors among beetles from different lanterns, ranging from green to red. They have been used as model enzymes to investigate the relationship between structure and bioluminescence colors. However, until date only 4 active luciferases from the larval stage of railroadworms have been cloned and investigated: the red emitting luciferase from Phrixotrix hirtus head lanterns (PhRE); the green emitting luciferases from the lateral lanterns of Phrixotrix spp (PvGR), the yellow-green emitting luciferase from the dorsal lanterns of Phengodes sp (Ph) and Euryopa clarindae luciferase. Previous studies using PCR isolated sequences suggested that the luciferases from the head and lateral lanterns are paralogous, and that the head lanterns luciferases evolved by gene duplication from green emitting lateral lanterns luciferases. Here, by transcriptional analysis identified and cloned novel railroadworm luciferases from Brasilocerus sp, Phrixotrix hirtus and Mastinomorphus larvae, and compared them with the green and red light emitting luciferases from both cephalic and lateral lanterns. Larvae of Brasilocerus display a single luciferase isozyme emitting yellow-green light in both the cephalic and lateral lanterns, whereas Phrixotrix spp and Mastinomorphus have two isozymes. The luciferases from lateral the lanterns display slower luminescence reaction kinetics with higher values of K_M for luciferin, whereas orange emitting luciferase display faster kinetics and lower K_M approaching those of the red emitting cephalic lanterns luciferase. The results indicate that, in contrast with Phrixotrix spp, some basal genera of Mastinocerinae railroadworms display a single isozyme in both the lateral and cephalic lanterns, and that the red light emitting luciferase of Phrixotrix is an apomorphic character that may have evolved quite recently in the cephalic lanterns of Phrixotrix lineage.