Molecular cloning, origin, and expression of saxitoxin biosynthesis gene sxtB from the toxic dinoflagellate Alexandrium catenella

Environmental Factors Modulate Saxitoxins (STXs) Production in Toxic Dinoflagellate Alexandrium: An Updated Review of STXs and Synthesis Gene Aspects

“…Moreover, genes participating in the tailoring, regulation, and transportation of STXs are involved in synthesizing various PST analogs [130][131][132][133]. Similarly, toxic dinoflagellates have sxt gene homologs to cyanobacteria [12,[134][135][136]. Among the genes, sxtA is known to be involved in the initial stage of STX synthesis and is the most widely studied [140].…”

“…Instead, the author suggested that STX tailoring genes (sxtX and sxtN) may be involved in the structural conversion from STX to other derivatives, including GTXs and dcGTXs. Besides sxtA and sxtG, recent studies reported the full-length sequences of sxtB [136], sxtU [146], and sxtI [63] from Alexandrium spp., and showed the correlation between their expression, toxin production, and environmental changes. Since each STXs metabolite has a different TEF, affecting the total STXs eq [16], it is contradictory to interpret the reduction in STXs eq as a decrease that is an absolute reduction.…”