Isolation and Expression Analysis of Growth-Related Genes at Different Growth Stages of Dinoflagellate Alexandrium pacificum

Abstract

Based on the transcriptomic sequencing, three genes of Alexandrium pacificum encoding ubiquitin (UBI), telomerase (TEL) and glycine-rich protein (GRP) relating to cell division were isolated and characterized. The full-length cDNA of GRP was obtained through approach of rapid amplification of cDNA ends (RACE). Four conserved domains, including DNA- and RNAbinding sites or motifs, cold shock domain at the N-terminal, and zinc-finger structure of CCCH type at the C-terminal were idenrtified. Phylogenetic analysis revealed that the deduced amino acid sequence of GRP tends to cluster together with proteins harboring cold shock domain. The expressions of these three genes were analyzed with quantitative PCR (qPCR). It was found that the expressions of these three genes at the logarithmic growth phase and induced logarithmic growth phase were all higher than those at lagging growth phase (P < 0.05). The expression patterns of these three genes were coincident with the proliferative capacity of the algae, e.g., displaying increased expression level at log and induced growth phases. The functions of these genes and their possible roles during harmful algal blooms (HAB) were discussed.