Gene expression and protein distribution of inter-alpha-trypsin inhibitor in three human hepatoma cell lines.
In standard culture conditions, three human hepatoma cell lines, Hep3B, PLC/PRF/5 and HepG2, were characterised by a predominant transcription of only two (H2 and L) among the four genes involved in the synthesis of inter-alpha-trypsin inhibitor (ITI)-related proteins. Pulse-chase experiments followed by immuno-precipitation with specific anti-L and anti-H ITI antisera showed that the proteins synthesised displayed a restricted L and/or H2 antigenic reactivity. Furthermore, while Hep3B and PLC/PRF/5 lines only synthesised ITI precursors (mainly the L-form), HepG2 cells were able to secrete an ITI-like protein. Immunocytochemical analyses substantiated these results with uneven distribution of heavy and light-chain polypeptide reactivity among the cells. The use of hepatoma cell models for the study of protein synthesis and assembly must therefore be considered cautiously.
Héron
A
A
INSERM Unité 295, Faculté de Médecine-Pharmacie de Rouen, St Etienne Rouvray, France.
Borghi
H
H
Callé
A
A
Bourguignon
J
J
Diarra-Mehrpour
M
M
Martin
J P
JP
Sesboüé
R
R
D000510:Alpha-Globulins / Q000032:analysis* / Q000096:biosynthesis* / Q000235:genetics / Q000378:metabolism; D006528:Carcinoma, Hepatocellular / Q000378:metabolism*; D002467:Cell Nucleus / Q000737:chemistry; D003593:Cytoplasm / Q000737:chemistry; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D011498:Protein Precursors / Q000096:biosynthesis; D012333:RNA, Messenger / Q000096:biosynthesis; D012334:RNA, Neoplasm / Q000096:biosynthesis; D014407:Tumor Cells, Cultured
D000510:Alpha-Globulins; D011498:Protein Precursors; D012333:RNA, Messenger; D012334:RNA, Neoplasm; C011877:inter-alpha-inhibitor