Increased steady-state levels of several mitochondrial and nuclear gene transcripts in rat hepatoma with a low content of mitochondria.

Abstract

Cells from a rapidly growing rat Zajdela hepatoma were shown to contain (on a protein basis) five-times less mitochondria than hepatocytes from resting or regenerating rat liver. Transcripts of four nuclear genes for representative mitochondrial membrane proteins (beta-F1 subunit and N,N'-dicyclohexyl-carbodiimide-binding protein of ATP synthase, subunit IV of cytochrome oxidase and ADP/ATP translocase) were present in 2-4 times higher amounts in the poly(A)-rich RNA of the hepatoma than in the corresponding RNA fraction from resting or regenerating rat liver. The liver and hepatoma transcripts for the beta-F1 subunit were translated in an in-vitro system with equal efficiency. Pulse-chase labeling of isolated Zajdela hepatoma cells and hepatocytes from resting and regenerating liver revealed a relative excess of the newly synthesized beta-F1 subunit in the tumor cells. The half-life of the beta-F1 subunit was significantly shorter in the hepatoma cells than in hepatocytes from resting and regenerating liver. The contents of transcripts of three mitochondrial genes examined (cytochrome oxidase subunits I and II and NADH-ubiquinone reductase subunit 2) in Zajdela hepatoma mitochondria were about five-times higher than in the mitochondria of the resting cells and 3-4 times higher than in the organelles of the regenerating organ. The results indicate that events other than transcription (most likely post-translational) may be responsible for the reduced content of mitochondria in tumor cells.

• Authors: K Luciaková, S Kuzela
• Journal: European journal of biochemistry (Eur J Biochem) Vol. 205 Issue 3 Pg. 1187-93 (May 01 1992) ISSN: 0014-2956 [Print] England
• PMID: 1374334 (Publication Type: Journal Article)

Chemical References

• DNA Probes
• DNA, Mitochondrial
• Nuclear Proteins
• RNA, Messenger
• Poly A
• RNA
• Proton-Translocating ATPases

Topics

• Animals
• Blotting, Northern
• Cell Nucleus (metabolism)
• DNA Probes
• DNA, Mitochondrial (genetics)
• Electrophoresis, Gel, Pulsed-Field
• Liver (cytology, enzymology, physiology)
• Liver Neoplasms, Experimental (enzymology, metabolism)
• Liver Regeneration
• Male
• Mitochondria, Liver (metabolism)
• Nuclear Proteins (genetics)
• Poly A (genetics)
• Protein Biosynthesis
• Proton-Translocating ATPases (biosynthesis)
• RNA (genetics)
• RNA, Messenger
• Rats
• Rats, Inbred Strains
• Transcription, Genetic