A conserved CCCH-type zinc finger protein regulates mRNA nuclear adenylation and export.
Coupling of messenger RNA (mRNA) nuclear export with prior processing steps aids in the fidelity and efficiency of mRNA transport to the cytoplasm. In this study, we show that the processes of export and polyadenylation are coupled via the Drosophila melanogaster CCCH-type zinc finger protein CG6694/dZC3H3 through both physical and functional interactions. We show that depletion of dZC3H3 from S2R+ cells results in transcript hyperadenylation. Using targeted coimmunoprecipitation and liquid chromatography mass spectrometry (MS)/MS techniques, we characterize interactions of known components of the mRNA nuclear export and polyadenylation machineries with dZC3H3. Furthermore, we demonstrate the functional conservation of this factor, as depletion of its human homologue ZC3H3 by small interfering RNA results in an mRNA export defect in human cells as well. Nuclear polyadenylated (poly(A)) RNA in ZC3H3-depleted cells is sequestered in foci removed from SC35-containing speckles, indicating a shift from the normal subnuclear distribution of poly(A) RNA. Our data suggest a model wherein ZC3H3 interfaces between the polyadenylation machinery, newly poly(A) mRNAs, and factors for transcript export.
Department of Systems Biology, Harvard Medical School, Boston, MA 02115, USA.
Jessica A
JA
Hurt
Robert A
RA
Obar
Bo
B
Zhai
Natalie G
NG
Farny
Steven P
SP
Gygi
Pamela A
PA
Silver
D021581:Active Transport, Cell Nucleus / Q000502:physiology*; D000818:Animals; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism*; D002460:Cell Line; D029721:Drosophila Proteins / Q000235:genetics / Q000378:metabolism*; D004331:Drosophila melanogaster / Q000235:genetics / Q000378:metabolism; D005786:Gene Expression Regulation; D006801:Humans; D029543:Nucleocytoplasmic Transport Proteins / Q000235:genetics / Q000378:metabolism; D039122:Poly(A)-Binding Protein I / Q000235:genetics / Q000378:metabolism; D034443:RNA Transport / Q000502:physiology*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism*; D034741:RNA, Small Interfering / Q000235:genetics / Q000378:metabolism; D016601:RNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D016335:Zinc Fingers
D002352:Carrier Proteins; D029721:Drosophila Proteins; C122111:NXF1 protein, human; D029543:Nucleocytoplasmic Transport Proteins; D039122:Poly(A)-Binding Protein I; D012333:RNA, Messenger; D034741:RNA, Small Interfering; D016601:RNA-Binding Proteins; D011993:Recombinant Fusion Proteins; C540588:ZC3H3 protein, Drosophila