The Arabidopsis splicing factors, AtU2AF65, AtU2AF35, and AtSF1 shuttle between nuclei and cytoplasms

Plant Cell Rep. 2017 Jul;36(7):1113-1123. doi: 10.1007/s00299-017-2142-z. Epub 2017 Apr 21.

Abstract

The Arabidopsis splicing factors, AtU2AF65, AtU2AF35, and AtSF1 shuttle between nuclei and cytoplasms. These proteins also move rapidly and continuously in the nuclei, and their movements are affected by ATP depletion. The U2AF65 proteins are splicing factors that interact with SF1 and U2AF35 proteins to promote U2snRNP for the recognition of the pre-mRNA 3' splice site during early spliceosome assembly. We have determined the subcellular localization and movement of these proteins' Arabidopsis homologs. It was found that Arabidopsis U2AF65 homologs, AtU2AF65a, and AtU2AF65b proteins interact with AtU2AF35a and AtU2AF35b, which are Arabidopsis U2AF35 homologs. We have examined the mobility of these proteins including AtSF1 using fluorescence recovery after photobleaching and fluorescence loss in photobleaching analyses. These proteins displayed dynamic movements in nuclei and their movements were affected by ATP depletion. We have also demonstrated that these proteins shuttle between nuclei and cytoplasms, suggesting that they may also function in cytoplasm. These results indicate that such splicing factors show very similar characteristics to their human counterparts, suggesting evolutionary conservation.

Keywords: Dynamic movement; FLIP; FRAP; SF1; Shuttling; U2AF35; U2AF65.

MeSH terms

  • Arabidopsis / metabolism*
  • Arabidopsis Proteins / genetics
  • Arabidopsis Proteins / metabolism*
  • Cell Nucleus / metabolism*
  • Cytoplasm / metabolism*
  • Protein Transport / genetics
  • Protein Transport / physiology
  • RNA Splicing Factors / genetics
  • RNA Splicing Factors / metabolism*

Substances

  • Arabidopsis Proteins
  • At5g51300 protein, Arabidopsis
  • RNA Splicing Factors