Drosophila ELL is associated with actively elongating RNA polymerase II on transcriptionally active sites in vivo.
Several factors have been biochemically characterized based on their ability to increase the overall rate of transcription elongation catalyzed by the multiprotein complex RNA polymerase II (Pol II). Among these, the ELL family of elongation factors has been shown to increase the catalytic rate of transcription elongation in vitro by suppressing transient pausing. Several fundamental biological aspects of this class of elongation factors are not known. We have cloned the Drosophila homolog (dELL) in order to test whether ELL family proteins are actually associated with the elongating Pol II in vivo. Here we report that dELL is a nuclear protein, which, like its mammalian homologs, can increase the catalytic rate of transcription elongation by Pol II in vitro. Interestingly, we find that dELL co-localizes extensively with the phosphorylated, actively elongating form of Pol II at transcriptionally active sites on Drosophila polytene chromosomes. Furthermore, dELL is relocalized from a widespread distribution pattern on polytenes under normal conditions to very few transcriptionally active puff sites upon heat shock. This observation indicates a dynamic pattern of localization of dELL in cells, which is a predicted characteristic of a Pol II general elongation factor. We also demonstrate that dELL physically interacts with Pol II. Our results strongly suggest that dELL functions with elongating RNA polymerase II in vivo.
Gerber
M
M
The Edward Doisy Department of Biochemistry and Molecular Biology, St Louis University School of Medicine, 1402 South Grand Blvd, Saint Louis, MO 63104, USA.
Ma
J
J
Dean
K
K
Eissenberg
J C
JC
Shilatifard
A
A
D000818:Animals; D002467:Cell Nucleus / Q000378:metabolism / Q000648:ultrastructure; D002875:Chromosomes / Q000378:metabolism / Q000648:ultrastructure; D003001:Cloning, Molecular; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D029721:Drosophila Proteins / Q000235:genetics / Q000378:metabolism; D004331:Drosophila melanogaster; D004625:Embryo, Nonmammalian / Q000166:cytology / Q000378:metabolism; D018507:Gene Expression Regulation, Developmental; D006360:Heat-Shock Proteins / Q000235:genetics; D018869:Heat-Shock Response / Q000502:physiology; D007150:Immunohistochemistry; D046911:Macromolecular Substances; D008969:Molecular Sequence Data; D046912:Multiprotein Complexes; D009363:Neoplasm Proteins; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism; D010445:Peptide Elongation Factors / Q000235:genetics / Q000378:metabolism*; D011485:Protein Binding / Q000502:physiology; D012319:RNA Polymerase II / Q000378:metabolism*; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D014158:Transcription, Genetic / Q000502:physiology*; D035602:Transcriptional Elongation Factors
D004268:DNA-Binding Proteins; D029721:Drosophila Proteins; C090862:ELL protein, human; D006360:Heat-Shock Proteins; D046911:Macromolecular Substances; D046912:Multiprotein Complexes; D009363:Neoplasm Proteins; D009687:Nuclear Proteins; D010445:Peptide Elongation Factors; D014157:Transcription Factors; D035602:Transcriptional Elongation Factors; D012319:RNA Polymerase II