Proliferating cell nuclear antigen expression in maize seed development and germination: Regulation by phytohormones and its association with putative cell cycle proteins

Abstract

The proliferating cell nuclear antigen (PCNA) plays a fundamental role in DNA replication and repair and recently, it has been found associated to proteins that control the G1 phase of the cell cycle, such as cyclin D. Maize PCNA cDNA has been cloned and overexpressed in order to raise antibodies. The expression of PCNA has been followed during seed development and seed germination using the homologous antibodies. The protein was found at a constant level during seed development up to 48 days after pollination (DAP) and then the amount declined to very low levels, similar to those found in dry seeds. Upon germination, PCNA levels rose gradually reaching a peak by 20 h germination. Imbibition in the presence of cytokinins (Benzyladenine, BA) produced a sharp increase in amount during the first 3–6 h germination, whereas imbibition in the presence of abscisic acid (ABA) did not alter the pattern of expression as compared with control seeds. Immunoprecipitation experiments showed that PCNA was associated to a putative cyclin D protein during germination and this association was altered by phytohormones. While the complex PCNA‐cyclin D‐like protein was present along the first 15 h of germination under control conditions, it was dissociated after 6 h if embryo axes germinated in the presence of BA or ABA. However, complex dissociation in the presence of BA was due to degradation of the putative cyclin D protein while in the presence of ABA the putative cyclin D was still present. These results are discussed in the context of seed germination and the cell cycle.

Abscisic Acid Is a General Negative Regulator of Arabidopsis Axillary Bud Growth

“…Previous studies showed that PCNA expression was up-regulated in buds of pea within 4 h following a decapitation treatment that promoted bud outgrowth (Shimizu and Mori, 1998) and was downregulated in sorghum (Sorghum bicolor) axillary buds suppressed by low R:FR or defoliation . ABA had little effect on PCNA protein accumulation in maize seeds (Herrera et al, 2000), suggesting that its effects on expression may depend on the type or developmental stage of the tissue. PCNA1 is a multifunctional protein that is involved in DNA repair and also acts as a processivity factor during DNA replication (Strzalka and Ziemienowicz, 2011).…”

A proposed conserved role for an avocado fw2.2-like gene as a negative regulator of fruit cell division

“…Towards this end, we isolated two avocado cDNAs encoding mitotic A-and B-type cyclins, together with a third cDNA encoding a putative proliferating cell nuclear antigen (PCNA), serving as a G1-S transition state marker (Citterio et al 1992;Herrera et al 2000) and monitored their developmental expression proWles in NF and SF tissues. Secondly, we performed parallel developmental studies of cell division (cell number) and cell expansion (cell area).…”

Regulating DNA Replication in Plants

“…It is frequent that plant genomes contain two PCNA genes, in contrast to PCNA pseudogenes normally found in mammalian cells. Plant PCNA forms a homotrimeric complex (Sanchez et al 2002;Strzalka et al 2009) that binds to various cyclin-CDK complexes (Herrera et al 2000;Sanchez et al 2005). In agreement with the hypothesis of serving as a sliding platform to other proteins, in vitro assays showed that PCNA-associated cyclin/CDK activity phosphorylates DNA polymerase a.…”