Interactional similarities and differences in the protein complex of PCNA and DNA replication factor C between rice and Arabidopsis

Jie Qian,Yueyue Chen,Yaxing Xu,Zhuang Kang,Xiufeng Zhang,Jinxia Jiao,Jie Zhao

doi:10.1186/s12870-019-1874-z

Abstract

BackgroundProliferating cell nuclear antigen (PCNA), a conserved trimeric ring complex, is loaded onto replication fork through a hetero-pentameric AAA+ ATPase complex termed replication factor C (RFC) to maintain genome stability. Although architectures of PCNA-RFC complex in yeast have been revealed, the functions of PCNA and protein-protein interactions of PCNA-RFC complex in higher plants are not very clear. Here, essential regions mediating interactions between PCNA and RFC subunits in Arabidopsis and rice were investigated via yeast-two-hybrid method and bimolecular fluorescence complementation techniques.ResultsWe observed that OsPCNA could interact with all OsRFC subunits, while protein-protein interactions only exist between Arabidopsis RFC2/3/4/5 and AtPCNA1/2. The truncated analyses indicated that the C-terminal of Arabidopsis RFC2/3/4/5 and rice RFC1/2 is essential for binding PCNA while the region of rice RFC3/4/5 mediating interaction with PCNA distributed both at the N- and C-terminal. On the other hand, we found that the C- and N-terminal of Arabidopsis and rice PCNA contribute equally to PCNA-PCNA interaction, and the interdomain connecting loop (IDCL) domain and C-terminal of PCNAs are indispensable for interacting RFC subunits.ConclusionsThese results indicated that Arabidopsis and rice PCNAs are highly conserved in sequence, structure and pattern of interacting with other PCNA monomer. Nevertheless, there are also significant differences between the Arabidopsis and rice RFC subunits in binding PCNA. Taken together, our results could be helpful for revealing the biological functions of plant RFC-PCNA complex.

Highlights

Proliferating cell nuclear antigen (PCNA), a conserved trimeric ring complex, is loaded onto replication fork through a hetero-pentameric AAA+ ATPase complex termed replication factor C (RFC) to maintain genome stability
The results showed that only yeast cells harboring AtRFC2/3/4/5-BD and AtPCNA1/2AD could survive on SD-medium lacking Leu, Trp, His, and Ade, while visible yeast could be observed among cells co-expressed OsRFC1/2/3/4/5-BD and OsPCNA-AD (Fig. 1)
These results indicated that Arabidopsis and rice PCNAs are highly conserved in sequence, structure and pattern of interacting with other PCNA monomer

Summary

Introduction

Proliferating cell nuclear antigen (PCNA), a conserved trimeric ring complex, is loaded onto replication fork through a hetero-pentameric AAA+ ATPase complex termed replication factor C (RFC) to maintain genome stability. Cells carried out highly processive, error-free replication of the genome in S-phase, and efficient repair of any DNA damage or misincorporated nucleotides. During these processes, a sliding clamp and its corresponding clamp loader are indispensable [1]. The ring-shaped clamp, which can encircle and slide freely along DNA, In yeast and human, PCNA is loaded onto the primertemplate junction by RFC complex to tether the DNA polymerase and assure the high-speed duplication when DNA replication begins [6].

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