Prohibitin antiproliferative activity and lack of heterozygosity in immortalized cell lines.
Experiments were performed to determine whether prohibitin, an evolutionarily conserved gene with antiproliferative activity, has a role in cellular immortalization. A cell proliferation assay was used to examine one human cell line from each of four established immortal complementation groups, termed A, B, C, and D, and a normal human diploid fibroblast line. Only normal and Group B cells were inhibited from traversing the cell cycle after introduction of wild-type prohibitin transcript. All of the immortalized cells expressed elevated levels of prohibitin mRNA and protein. Prohibitin gene structural characterization using Southern and single-strand conformation polymorphism (SSCP) analyses distinguished two alleles. One is cleaved at a polymorphic intronic EcoRI site, exhibits an exon 6-associated SSCP, and is homozygous only in Group B cells. The other is not cleaved at the EcoRI site, has a different exon 6 SSCP pattern, and is homozygous in Groups A, C, and D. In contrast, normal cells are heterozygous for the alleles. These results suggest that prohibitin may play a role as a tumor suppressor in the immortalization of Group B cells.
Jupe
E R
ER
Noble Center for Biomedical Research, Oklahoma Medical Research Foundation, Oklahoma City 73104, USA.
Liu
X T
XT
Kiehlbauch
J L
JL
McClung
J K
JK
Dell'Orco
R T
RT
D000483:Alleles; D002455:Cell Division / Q000235:genetics; D002461:Cell Line, Transformed; D005347:Fibroblasts / Q000166:cytology; D018628:Gene Dosage; D006720:Homozygote; D006801:Humans; D000091402:Prohibitins; D014176:Protein Biosynthesis; D011506:Proteins / Q000235:genetics*; D012333:RNA, Messenger / Q000032:analysis; D012097:Repressor Proteins
D000091402:Prohibitins; D011506:Proteins; D012333:RNA, Messenger; D012097:Repressor Proteins