TY - JOUR
T1 - Actin bound to the heterogeneous nuclear ribonucleoprotein hrp36 is associated with Balbiani ring mRNA from the gene to polysomes
AU - Percipalle, Piergiorgio
AU - Zhao, Jian
AU - Pope, Brian
AU - Weeds, Alan
AU - Lindberg, Uno
AU - Daneholt, Bertil
PY - 2001/4/2
Y1 - 2001/4/2
N2 - In the salivary glands of the dipteran Chironomus tentans, a specific messenger ribonucleoprotein (mRNP) particle, the Balbiani ring (BR) granule, can be visualized during its assembly on the gene and during its nucleocytoplasmic transport. We now show with immunoelectron microscopy that actin becomes associated with the BR particle concomitantly with transcription and is present in the particle in the nucleoplasm. DNase I affinity chromatography experiments with extracts from tissue culture cells indicate that both nuclear and cytoplasmic actin are bound to the heterogeneous RNP (hnRNP) protein hrp36, but not to the hnRNP proteins hrp23 and hrp45. The interaction is likely to be direct as purified actin binds to recombinant hrp36 in vitro. Furthermore, it is demonstrated by cross linking that nuclear as well as cytoplasmic actin are bound to hrp36 in vivo. It is known that hrp36 is added cotranscriptionally along the BR mRNA molecule and accompanies the RNA through the nuclear pores and into polysomes. We conclude that actin is likely to be bound to the BR transcript via hrp36 during the transfer of the mRNA from the gene all the way into polysomes.
AB - In the salivary glands of the dipteran Chironomus tentans, a specific messenger ribonucleoprotein (mRNP) particle, the Balbiani ring (BR) granule, can be visualized during its assembly on the gene and during its nucleocytoplasmic transport. We now show with immunoelectron microscopy that actin becomes associated with the BR particle concomitantly with transcription and is present in the particle in the nucleoplasm. DNase I affinity chromatography experiments with extracts from tissue culture cells indicate that both nuclear and cytoplasmic actin are bound to the heterogeneous RNP (hnRNP) protein hrp36, but not to the hnRNP proteins hrp23 and hrp45. The interaction is likely to be direct as purified actin binds to recombinant hrp36 in vitro. Furthermore, it is demonstrated by cross linking that nuclear as well as cytoplasmic actin are bound to hrp36 in vivo. It is known that hrp36 is added cotranscriptionally along the BR mRNA molecule and accompanies the RNA through the nuclear pores and into polysomes. We conclude that actin is likely to be bound to the BR transcript via hrp36 during the transfer of the mRNA from the gene all the way into polysomes.
KW - Actin
KW - Balbiani rings
KW - Heterogeneous nuclear ribonucleoprotein
KW - Nucleocytoplasmic transport
KW - Premessenger ribonucleoprotein particles
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U2 - 10.1083/jcb.153.1.229
DO - 10.1083/jcb.153.1.229
M3 - Article
C2 - 11285288
AN - SCOPUS:0035795419
SN - 0021-9525
VL - 153
SP - 229
EP - 235
JO - Journal of Cell Biology
JF - Journal of Cell Biology
IS - 1
ER -