Genome-wide analysis of mRNAs regulated by the THO complex in Drosophila melanogaster


In yeast cells, the THO complex has been implicated in mitotic recombination, transcription elongation and mRNA nuclear export. The stable core of THO consists of Tho2p, Hpr1p, Mft1p and Thp2p. Whether a complex with similar functions assembles in metazoa has not yet been established. Here we report that Drosophila melanogaster THO consists of THO2, HPR1 and three proteins, THOC5–THOC7, which have no orthologs in budding yeast. Gene expression profiling in cells depleted of THO components revealed that <20% of the transcriptome was regulated by THO. Nonetheless, export of heat-shock mRNAs under heat stress was strictly dependent on THO function. Notably, 8% of upregulated genes encode proteins involved in DNA repair. Thus, although THO function seems to be conserved, the vast majority of mRNAs are transcribed and exported independently of THO in D. melanogaster.

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Figure 1: Purification of the stable core of the D. melanogaster THO complex.
Figure 2: The THO complex is required for cell proliferation.
Figure 3: Depletion of both THO2 and HPR1 causes the accumulation of poly(A)+ RNA in the nucleus.
Figure 4: Inhibition of the heat-shock response in THO-depleted cells.
Figure 5: The THO complex is required for the export of heat-shock mRNAs.
Figure 6: Depletion of both THO2 and HPR1 affects the expression of <20% of the D. melanogaster transcriptome.
Figure 7: Potential mRNA export substrates of THO.
Figure 8: A small set of mRNAs show similar expression profiles in cells depleted of NXF1, UAP56 or THO components.
Figure 9: Comparison of mRNA expression profiles in cells depleted of NXF1, UAP56 or THO components.

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We are grateful to members of the Gene Core Facility at European Molecular Biology Laboratory for performing the array hybridizations, L. Juhl-Jensen for help with the annotation of D. melanogaster genes, L. Steinmetz for helpful discussions and D. Thomas for comments on the manuscript. This study was supported by the Human Frontier Science Program Organization (HFSPO).

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Correspondence to Elisa Izaurralde.

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Rehwinkel, J., Herold, A., Gari, K. et al. Genome-wide analysis of mRNAs regulated by the THO complex in Drosophila melanogaster. Nat Struct Mol Biol 11, 558–566 (2004).

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