[Chromatin proteins binding vitamin E]

Area of Science:

• Biochemistry
• Molecular Biology
• Cell Biology

Context:

• Nuclear extracts contain tocopherol-binding proteins crucial for alpha-tocopherol (vitamin E) interaction with chromatin.
• Specific binding activity of [H] alpha-tocopherol to chromatin was identified in fractions eluted with 2M NaCl + 5M urea during hydroxyapatite chromatography.
• Quantitative alterations in the protein content of this specific fraction were observed during hypovitaminosis.

Purpose:

• To investigate the specific binding of alpha-tocopherol to isolated chromatin.
• To identify the protein components involved in alpha-tocopherol binding to chromatin.
• To determine the effect of vitamin E on nuclear matrix RNA polymerase activity and its dependence on chromatin-associated proteins.

Summary:

• Alpha-tocopherol binding to isolated chromatin is specific only when tocopherol-binding proteins from a nuclear extract are present.
• A specific binding activity for [H] alpha-tocopherol was detected in a fraction eluted with 2M NaCl + 5M urea after hydroxyapatite chromatography of incubated chromatin.
• Quantitative changes in this fraction's protein content were observed during hypovitaminosis, and vitamin E was shown to affect in vitro RNA polymerase activity of the nuclear matrix, suggesting the necessity of tocopherol-binding proteins for this effect.

Impact:

• This research elucidates the mechanism of alpha-tocopherol's interaction with chromatin, highlighting the role of specific binding proteins.
• The findings suggest a novel pathway for vitamin E's biological activity through modulation of RNA polymerase activity.
• Understanding these interactions could have implications for cellular processes regulated by vitamin E and nuclear matrix function.