Nuclear actin is associated with a specific subset of hnRNP A/B-type proteins
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 spect...
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Published in | Nucleic acids research Vol. 30; no. 8; pp. 1725 - 1734 |
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Main Authors | , , , , , , |
Format | Journal Article |
Language | English |
Published |
England
Oxford University Press
15.04.2002
Oxford Publishing Limited (England) |
Subjects | |
Online Access | Get full text |
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Summary: | 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. |
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Bibliography: | Received January 15, 2002; Revised and Accepted February 22, 2002. local:gkf275 istex:B6C40C0BDD90D7EE9CE8901BF5C9FFA584F955EF ark:/67375/HXZ-D5BXR55B-8 ObjectType-Article-2 SourceType-Scholarly Journals-1 ObjectType-Feature-1 content type line 23 ObjectType-Article-1 ObjectType-Feature-2 To whom correspondence should be addressed. Tel: +46 8 7287370; Fax: +46 8 313529; Email: bertil.daneholt@cmb.ki.se |
ISSN: | 0305-1048 1362-4962 1362-4962 |
DOI: | 10.1093/nar/30.8.1725 |