Nuclear actin is associated with a specific subset of hnRNP A/B-type proteins

Piergiorgio Percipalle, Andreas Jonsson, Dmitri Nashchekin, Christina Karlsson, Tomas Bergman, Apostolia Guialis, Bertil Daneholt

Research output: Contribution to journalArticlepeer-review


Pre-mRNP complexes were isolated from rat liver nuclei as 40S hnRNP particles, and actin-binding proteins were collected by DNase I affinity chromatography. The bound proteins were analyzed by 2D gel electrophoresis, and the following five hnRNP A/B-type proteins were identified by tandem mass spectrometry: DBP40/CBF-A (CArG binding factor A), a minor hnRNP A2 variant and three minor hnRNP A3 (mBx) variants. DBP40 was chosen for further analysis of the association of actin with the pre-mRNP complex. It was shown in vitro that purified actin binds to recombinant DBP40 suggesting that the interaction between actin and DBP40 is direct in the pre-mRNP particles. The association of actin with DBP40 was further explored in vivo. It was shown in a transfection study that DBP40 appears both in the nucleus and cytoplasm. Microinjection experiments revealed that DBP40 is exported from the nucleus to the cytoplasm. Finally, RNA-protein and protein-protein cross-linking experiments showed that DBP40 interacts with poly(A)+ RNA as well as actin, both in the nucleus and cytoplasm. We propose that actin associated with DBP40, and perhaps with additional hnRNP A/B-type proteins, is transferred from nucleus to cytoplasm bound to mRNA.

Original languageEnglish (US)
Pages (from-to)1725-1734
Number of pages10
JournalNucleic acids research
Issue number8
StatePublished - Apr 15 2002

ASJC Scopus subject areas

  • Genetics


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