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Tissue-specific chromosomal non-histone protein interactions with DNA.
The Journal of Biological Chemistry
|March 10, 1976
Summary
Chromosomal non-histone proteins (NP) bind unique DNA sequences in rat liver and Novikoff hepatoma. These tissue-specific NP-DNA complexes associate with active chromatin in hepatoma cells.
Area of Science:
- Molecular Biology
- Biochemistry
- Genetics
Background:
- Chromatin structure and function are regulated by non-histone proteins.
- Understanding DNA-binding proteins is crucial for deciphering gene regulation.
Purpose of the Study:
- To isolate and characterize chromosomal non-histone proteins (NP) with DNA affinity from rat liver and Novikoff hepatoma.
- To investigate the binding specificity and immunological properties of these NP fractions.
Main Methods:
- Isolation of chromosomal non-histone proteins (NP) from rat liver and Novikoff hepatoma.
- DNA binding assays to determine affinity and specificity.
- Microcomplement fixation assays for immunological characterization.
Main Results:
- A fraction of chromosomal non-histone proteins (NP), <5% of total chromatin protein, was isolated.
- NP binds preferentially to unique, double-stranded homologous DNA sequences with high affinity (Km = 6.7 X 10(-9) M) at low ionic strength.
- NP-DNA complexes are immunologically tissue-specific.
- In Novikoff hepatoma, NP proteins are associated with the transcriptionally active, diffuse chromatin fraction.
Conclusions:
- Chromosomal non-histone proteins exhibit specific DNA binding properties.
- These NP proteins are involved in tissue-specific interactions with DNA.
- NP proteins are linked to the regulation of transcription in active chromatin regions.