TY - JOUR
T1 - Squid hnRNP protein promotes apical cytoplasmic transport and localization of Drosophila pair-rule transcripts
AU - Lall, Sabbi
AU - Francis-Lang, Helen
AU - Flament, Antonin
AU - Norvell, Amanda
AU - Schüpbach, Trudi
AU - Ish-Horowicz, David
N1 - Funding Information:
We are grateful to Daniel St Johnston for encouraging us to try mRNA injection experiments, and to Iain Mattaj, Elsbeth Lund, and an early anonymous reviewer for suggesting the use of nuclear extracts. We thank Sheetal Shah for proposing the use of double-label fluorescence to compare transcript behavior, Jolanta B. Glotzer and Ann Ephrussi for communication of the fluorescent labeling protocol prior to publication, Kim Mowry for communicating unpublished results, Rainer Pepperkok and Peter Jordan for advice on confocal microscopy, Sheena Pinchin for advice on transcript injections, and many colleagues for helpful comments and critical reading of the manuscript. We also thank Daniel St Johnston, Peter Verrijzer, Susana Llanos, Gordon Peters, Anne Couturier, and Gideon Dreyfuss for generous gifts of anti-Staufen antibody, bcd-3′UTR DNA, nuclear extracts, GST-PABP, and Sqd antibody, and Adrian Krainer for gifts of human hnRNP proteins. This work was supported by the Imperial Cancer Research Fund, an American Cancer Society Fellowship (A. N.), and grants from the Howard Hughes Medical Institute to D. I.-H. through the International Research Scholars Program, and to T. S. who is an HHMI Associate Investigator.
PY - 1999/7/23
Y1 - 1999/7/23
N2 - Drosophila melanogaster pair-rule segmentation gene transcripts localize apically of nuclei in blastoderm embryos. This might occur by asymmetric (vectorial) export from one side of the nucleus or by transport within the cytoplasm. We have followed fluorescently labeled pair-rule transcripts postinjection into Drosophila embryos. Naked, microinjected fushi tarazu (ftz) transcripts do not localize in blastoderm embryos, indicating that cytoplasmic mechanisms alone are insufficient for apical targeting. However, prior exposure of ftz to Drosophila or human embryonic nuclear extract leads to rapid, specific, microtubule-dependent transport, arguing against vectorial export. We present evidence that ftz transcript localization involves the Squid (Hrp40) hnRNP protein and that the activity of hnRNP proteins in promoting transcript localization is evolutionarily conserved. We propose that cytoplasmic localization machineries recognize transcripts in the context of nuclear partner proteins.
AB - Drosophila melanogaster pair-rule segmentation gene transcripts localize apically of nuclei in blastoderm embryos. This might occur by asymmetric (vectorial) export from one side of the nucleus or by transport within the cytoplasm. We have followed fluorescently labeled pair-rule transcripts postinjection into Drosophila embryos. Naked, microinjected fushi tarazu (ftz) transcripts do not localize in blastoderm embryos, indicating that cytoplasmic mechanisms alone are insufficient for apical targeting. However, prior exposure of ftz to Drosophila or human embryonic nuclear extract leads to rapid, specific, microtubule-dependent transport, arguing against vectorial export. We present evidence that ftz transcript localization involves the Squid (Hrp40) hnRNP protein and that the activity of hnRNP proteins in promoting transcript localization is evolutionarily conserved. We propose that cytoplasmic localization machineries recognize transcripts in the context of nuclear partner proteins.
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U2 - 10.1016/S0092-8674(00)81012-0
DO - 10.1016/S0092-8674(00)81012-0
M3 - Article
C2 - 10428029
AN - SCOPUS:0033597716
SN - 0092-8674
VL - 98
SP - 171
EP - 180
JO - Cell
JF - Cell
IS - 2
ER -