A conserved family of nuclear phosphoproteins localized to sites of polymerase II transcription.
An antibody was identified previously that recognizes sites of polymerase II transcription on lampbrush chromosomes, puffs on polytene chromosomes, and many small granules in the nucleoplasm of all cells tested. This antibody binds a conserved family of phosphorylated polypeptides in vertebrate and invertebrate cells. We developed a method for purifying these proteins that involves differential solubility in MgCl2. We isolated a Drosophila cDNA encoding one of the proteins using information obtained from microsequencing. In vivo expression studies show that this protein is concentrated on sites of polymerase II transcription and that it is highly phosphorylated. The protein shares a high degree of homology with proteins involved in alternative splicing of pre-mRNA suggesting the possibility that this protein plays a role in pre-mRNA splicing.
Roth
M B
MB
Fred Hutchinson Cancer Research Center, Seattle, Washington 98104.
Zahler
A M
AM
Stolk
J A
JA
D000595:Amino Acid Sequence; D000818:Animals; D000911:Antibodies, Monoclonal; D001483:Base Sequence; D004247:DNA / Q000235:genetics; D004257:DNA Polymerase II / Q000378:metabolism*; D004330:Drosophila / Q000235:genetics; D000939:Epitopes / Q000032:analysis; D005260:Female; D006367:HeLa Cells; D006801:Humans; D008969:Molecular Sequence Data; D009698:Nucleoproteins / Q000032:analysis / Q000235:genetics*; D009865:Oocytes / Q000502:physiology; D010750:Phosphoproteins / Q000032:analysis / Q000235:genetics*; D016133:Polymerase Chain Reaction / Q000379:methods; D014176:Protein Biosynthesis; D011994:Recombinant Proteins / Q000032:analysis; D014158:Transcription, Genetic; D014981:Xenopus
D000911:Antibodies, Monoclonal; D000939:Epitopes; D009698:Nucleoproteins; D010750:Phosphoproteins; D011994:Recombinant Proteins; D004247:DNA; D004257:DNA Polymerase II