Interaction between Nucleocapsid Protein and the Leader the Sequence of SARS-CoV RNA
Abstract: SARS coronavirus(SARS-CoV) is a novel human coronavirus and was responsible for SARS outbreak in several regions of the world in 2003.The genome of SARS-CoV is about 30,000 nucleotides in length and sequence analysis revealed that nucleotides 1-72 contain a RNA leader sequence preceding an untranslated region(UTR).In order to confirm the interaction between the N protein and the RNA leader sequence,the N gene was cloned,sequenced and the protein was expressed in Escherichia coli as a fusion protein with His-tag.The recombination N protein was purified by Ni-NTA affinity column and G-75 column.Meanwhile,the DIG labeled RNA leader sequences were synthesized by in vitro transcription.RNA-Protein interaction was detected by Northwestern RNA blot assay.The results indicated that a specific interaction takes place between the N protein and RNA leader sequence.Our results provide some insights into the understanding of assembly of the SARS-CoV particles,which is an essential step for viral replication cycle.