Proliferating cell nuclear antigen (PCNA) as a marker of cell proliferation in the marine dinoflagellate Prorocentrum donghaiense Lu and the green alga Dunaliella salina Teodoresco

Abstract

Proliferating cell nuclear antigen (PCNA) was detected in Prorocentrum donghaiense Lu and Dunaliella salina Teodoresco by enhanced chemiluminescence techniques with one mono-antibody. The observed band detected on western blots of P. donghaiense and D. salina had a molecular weight of 36-33 kDa rather than a PCNA-like protein with a size of 55 kDa reported in the dinoflagellates Crypthecodinium cohnii Biecheler and Gymnodinium catenatum Brav. The abundance of PCNA proteins was growth-stage dependent. Whole-cell immunoflurescence labeling showed that the PCNA antibody specifically stained the target proteins in P. donghaiense and D. salina, and PCNA is only present in the nucleus during the cell cycle. Synchronized cells of P. donghaiense show a cell cycle specific expression pattern with the highest expression in S phase and little expression in the G 1 and G 2 /M phases. The results demonstrated that the PCNA-like proteins could be a marker for the estimation of marine phytoplankton growth rates. The different sizes of the PCNA-like proteins observed in dinoflagellates could be related to the variety of dinoflagellate chromosomal structure.

Validation of reference genes for cryopreservation studies with the gorgonian coral endosymbiont Symbiodinium

“…At the transcriptional level, pcna mRNA is stable and its expression is not affected by different growth phases of cells36. However, this is not observed in other dinoflagellates37. Although we used different stress treatments in the present study, our results were consistent with those of Boldt et al 20.…”

Cloning of proliferating cell nuclear antigen gene from the dinoflagellate Prorocentrum donghaiense and monitoring its expression profiles by real-time RT-PCR

“…Some scholars have expressed the viewpoint that the abundance of PCNA-like proteins are growthstage dependent in Haptophyceae, Chlorophyta, and Dinoflagellates using an anti-rat-PCNA monoclonal antibody (Lin & Corstjens, 2002;Liu et al, 2005;Zhang et al, 2006). In the present study, we cloned the PCNA gene and obtained a better relationship between PCNA gene expression level and growth rate of P. donghaiense.…”

“…PCNA has been shown to vary between the S phase and the remainder of the cell cycle Liu et al, 2005). Similarly, PCNA transcription and protein synthesis in chlorophytes, diatoms, haptophytes, and dinoflagellates are elevated in the exponential phase than in the stationary phase (Lin et al, 1994(Lin et al, , 1995Cheng et al, 1997;Lin & Corstjens, 2002;Wei et al, 2004;Zhang et al, 2006).…”

“…Two highly conserved domains of PCNA, the binding site of replication factor C (-YLAPK-) and that of DNA polymerase d and p21 (-DSSHV-) (Lin & Corstjens, 2002), were also found in PCNA from P. donghaiense. However, PCNA is present in all organisms examined thus far, including marine phytoplankton (Lin et al, 1994;Kelman, 1997;Lin & Corstjens, 2002;Liu et al, 2005), and the gene sequences and protein structures are highly conserved as well . Based on evidence such as protein identity and phylogenetic tree analysis, we demonstrated that the sequence obtained in the present study was undoubtedly the PCNA gene from P. donghaiense.…”

“…However, compared with the more conventional methods of estimating phytoplankton growth rates, the major advantage of using a growth indicator is the elimination of adverse effects of bottle incubation (Furnas, 1990). To date, among microalgae, the PCNA gene and its encoded protein have been detected in chlorophytes (Lin et al, 1994, prasinophytes (Cheng et al, 1997), haptophytes Lin & Corstjens, 2002), diatoms (Wei et al, 2004), and dinoflagellates (Liu et al, 2005;Zhang et al, 2006). In addition, a positive correlation was found between PCNA gene expression and growth rate (Lin & Corstjens, 2002;Zhang et al, 2006), and PCNA protein abundance was growth-stage dependent (Lin & Corstjens, 2002;Liu et al, 2005;Zhang et al, 2006).…”