Hv1 Proton Channels in Dinoflagellates: Not Just for Bioluminescence?

Abstract

Bioluminescence in dinoflagellates is controlled by HV1 proton channels. Database searches of dinoflagellate transcriptomes and genomes yielded hits with sequence features diagnostic of all confirmed HV1, and show that HV1 is widely distributed in the dinoflagellate phylogeny including the basal species Oxyrrhis marina. Multiple sequence alignments followed by phylogenetic analysis revealed three major subfamilies of HV1 that do not correlate with presence of theca, autotrophy, geographic location, or bioluminescence. These data suggest that most dinoflagellates express a HV1 which has a function separate from bioluminescence. Sequence evidence also suggests that dinoflagellates can contain more than one HV1 gene.