Increased expression of apolipoprotein genes accompanies differentiation in the intestinal cell line Caco-2.
We have analyzed determinants of the synthesis and secretion of apolipoproteins including mRNA for apolipoproteins, in the human colon carcinoma cell line Caco-2 during differentiation in continuous culture. Significant increases in both cellular and secreted apolipoprotein A-I were observed early in the differentiation process. Increases in apolipoprotein B were limited to secreted protein and started later in the differentiation process. Levels of mRNA for apolipoproteins A-I, A-IV, B, C-III, and E increased significantly between the time cells reached confluence and 1 week postconfluence. The kinetics of mRNA accumulation were influenced by culture conditions. Nuclear extracts from postconfluent Caco-2 cells contained increased amounts of protein that bound to oligonucleotides containing the control regions of the apolipoprotein A-I and B genes. A competition experiment suggested that this protein recognized the control regions of both genes. We propose to name this protein DRIFT-1 (differentiation-related intestinal factor for transcription 1).
Reisher
S R
SR
Department of Genetics, University of Pennsylvania School of Medicine, Philadelphia 19104-6068.
Hughes
T E
TE
Ordovas
J M
JM
Schaefer
E J
EJ
Feinstein
S I
SI
D000230:Adenocarcinoma; D016632:Apolipoprotein A-I / Q000096:biosynthesis / Q000235:genetics; D053305:Apolipoprotein C-III; D001053:Apolipoproteins / Q000096:biosynthesis* / Q000235:genetics / Q000302:isolation & purification; D001054:Apolipoproteins A / Q000096:biosynthesis / Q000235:genetics; D001055:Apolipoproteins B / Q000096:biosynthesis / Q000235:genetics; D001056:Apolipoproteins C / Q000096:biosynthesis / Q000235:genetics; D001057:Apolipoproteins E / Q000096:biosynthesis / Q000235:genetics; D001483:Base Sequence; D001665:Binding Sites; D002454:Cell Differentiation; D002467:Cell Nucleus / Q000378:metabolism; D003110:Colonic Neoplasms; D004268:DNA-Binding Proteins / Q000378:metabolism; D015870:Gene Expression; D006801:Humans; D007700:Kinetics; D008969:Molecular Sequence Data; D009838:Oligodeoxyribonucleotides; D015345:Oligonucleotide Probes; D012333:RNA, Messenger / Q000378:metabolism*; D012334:RNA, Neoplasm / Q000235:genetics / Q000302:isolation & purification; D012689:Sequence Homology, Nucleic Acid; D013997:Time Factors; D014407:Tumor Cells, Cultured
D016632:Apolipoprotein A-I; D053305:Apolipoprotein C-III; D001053:Apolipoproteins; D001054:Apolipoproteins A; D001055:Apolipoproteins B; D001056:Apolipoproteins C; D001057:Apolipoproteins E; D004268:DNA-Binding Proteins; D009838:Oligodeoxyribonucleotides; D015345:Oligonucleotide Probes; D012333:RNA, Messenger; D012334:RNA, Neoplasm; C022205:apolipoprotein A-IV