Abstract
E2F is a heterodimeric transcription factor that regulates the expression of genes at the G1/S boundary and is composed of two related but distinct families of proteins, E2F and DP. E2F/DP heterodimers form complexes with the retinoblastoma (Rb) protein, the Rb-related proteins p107 and p130, and cyclins/cdks in a cell cycle-dependent fashion in vivo. E2F is encoded by at least five closely related genes, E2F-1 through -5. Here we report studies of DP-2, the second member of the DP family of genes. Our results indicate that (i) DP-2 encodes at least five distinct mRNAs, (ii) a site of alternative splicing occurs within the 5' untranslated region of DP-2 mRNA, (iii) at least three DP-2-related proteins (of 55, 48, and 43 kDa) are expressed in vivo, (iv) each of these proteins is phosphorylated, and (v) one DP-2 protein (43 kDa) carries a truncated amino terminus. Our data also strongly suggest that the 55-kDa DP-2-related protein is a novel DP-2 isoform that results from alternative splicing. Thus, we conclude that DP-2 encodes a set of structurally, and perhaps functionally, distinct proteins in vivo.
Publication types
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Research Support, Non-U.S. Gov't
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Research Support, U.S. Gov't, P.H.S.
MeSH terms
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Alternative Splicing
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Amino Acid Sequence
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Animals
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Base Sequence
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Carrier Proteins*
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Cell Cycle Proteins*
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Cell Line
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Chlorocebus aethiops
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DNA-Binding Proteins / biosynthesis*
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DNA-Binding Proteins / isolation & purification
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DNA-Binding Proteins / metabolism
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E2F Transcription Factors
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E2F1 Transcription Factor
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Electrophoresis, Polyacrylamide Gel
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Helix-Loop-Helix Motifs
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Methionine / metabolism
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Molecular Sequence Data
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Molecular Weight
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Multigene Family
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Phosphates / metabolism
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Phosphoproteins / isolation & purification
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Phosphoproteins / metabolism
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Phosphorus Radioisotopes
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Phosphorylation
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RNA, Messenger / biosynthesis
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Recombinant Proteins / biosynthesis
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Recombinant Proteins / isolation & purification
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Recombinant Proteins / metabolism
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Retinoblastoma Protein / metabolism
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Retinoblastoma-Binding Protein 1
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Saccharomyces cerevisiae
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Sequence Homology, Nucleic Acid
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Sulfur Radioisotopes
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Transcription Factor DP1
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Transcription Factors / biosynthesis*
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Transcription Factors / isolation & purification
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Transcription Factors / metabolism*
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Transcription, Genetic
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Transfection
Substances
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Carrier Proteins
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Cell Cycle Proteins
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DNA-Binding Proteins
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E2F Transcription Factors
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E2F1 Transcription Factor
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Phosphates
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Phosphoproteins
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Phosphorus Radioisotopes
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RNA, Messenger
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Recombinant Proteins
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Retinoblastoma Protein
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Retinoblastoma-Binding Protein 1
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Sulfur Radioisotopes
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Transcription Factor DP1
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Transcription Factors
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Methionine