Repression of the albumin gene in Novikoff hepatoma cells
Novikoff hepatoma cells have lost their capacity to synthesize albumin. As a first approach to study the mechanisms underlying this event, in vitro translation in a reticulocyte system was performed using total polyadenylated mRNA from rat liver and Novikoff hepatoma cells. Immunoprecipitation of the in vitro translation products with albumin-specific antibody revealed a total lack of albumin synthesis in Novikoff hepatoma, suggesting the absence of functional albumin mRNA in these cells. Titration experiments using as probe albumin cDNA cloned in pBR322 plasmid demonstrated the absence of albumin-specific sequences in both polysomal and nuclear polyadenylated and total RNA from Novikoff cells. This albumin recombinant plasmid was obtained by screening a rat liver cDNA library with albumin (/sup 32/P)cDNA reverse transcribed from immuno-precipitated mRNA. The presence of an albumin-specific gene insert was documented with translation assays as well as by restriction mapping. Repression of the albumin gene at the transcriptional level was further demonstrated by RNA blotting experiments using the cloned albumin cDNA probe. Genomic DNA blots using the cloned albumin cDNA as probe did not reveal any large-scale deletions, insertions, or rearrangements in the albumin gene, suggesting that the processes involved in the suppression of albumin mRNA synthesis do not involve extensive genomic rearrangements.
- Research Organization:
- California Institute of Technology, Div. of Biology, Pasadena, CA 91125
- OSTI ID:
- 5607072
- Journal Information:
- Mol. Cell. Biol.; (United States), Journal Name: Mol. Cell. Biol.; (United States) Vol. 2:3; ISSN MCEBD
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
59 BASIC BIOLOGICAL SCIENCES
ADENYLIC ACID
ALBUMINS
ANIMALS
ANTIBODIES
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BODY
CELL CONSTITUENTS
CELL CULTURES
CELL TRANSFORMATIONS
CHROMOSOME LOSSES
CLONING
DAYS LIVING RADIOISOTOPES
DIGESTIVE SYSTEM
DISEASES
DNA
DNA SEQUENCING
DNA-CLONING
GENE REGULATION
GENE REPRESSORS
GENES
GENETIC ENGINEERING
GENETIC MAPPING
GLANDS
HEPATOMAS
IN VITRO
ISOTOPE APPLICATIONS
ISOTOPES
LABELLING
LIGHT NUCLEI
LIVER
LOSSES
MAMMALS
MAPPING
MESSENGER-RNA
MOLECULAR BIOLOGY
NEOPLASMS
NUCLEI
NUCLEIC ACIDS
NUCLEOPROTEINS
NUCLEOTIDES
ODD-ODD NUCLEI
ONCOGENIC TRANSFORMATIONS
ORGANIC COMPOUNDS
ORGANS
PHOSPHORUS 32
PHOSPHORUS ISOTOPES
PLASMIDS
PRECIPITATION
PROTEINS
RADIOISOTOPES
RATS
RECOMBINANT DNA
RNA
RNA PROCESSING
RODENTS
SEPARATION PROCESSES
STRUCTURAL CHEMICAL ANALYSIS
TRACER TECHNIQUES
TRANSCRIPTION
VERTEBRATES