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A Protein Preparation Method for the High-throughput Identification of Proteins Interacting with a Nuclear Cofactor Using LC-MS/MS Analysis
Published on: January 24, 2017
Identification of specific polypeptides of the nuclear envelope by iodination of mouse liver nuclei
1Centre for Cellular and Molecular Biology, Hyderabad, India.
Insights
This study presents a rapid method for identifying nuclear envelope proteins using iodination. The technique successfully labeled 13 distinct polypeptides within the nuclear envelope.
Area of Science:
- Cell Biology
- Biochemistry
- Molecular Biology
Background:
- The nuclear envelope is a critical structure regulating molecular traffic between the nucleus and cytoplasm.
- Accurate identification of nuclear envelope proteins is essential for understanding nuclear function and cellular processes.
Purpose of the Study:
- To develop and validate a sensitive technique for the rapid identification of nuclear envelope proteins.
- To characterize the protein composition of the mouse liver nuclear envelope.
Main Methods:
- Purification of mouse liver nuclei using sucrose gradients.
- Iodination of purified nuclei with immobilized Na125I reagent (Iodogen).
- Enzymatic digestion (RNAase A, DNAase I), salt extraction, and SDS-PAGE for protein identification and characterization.
Main Results:
- Successfully isolated and labeled nuclear envelopes.
- Identified 13 distinct polypeptides in the nuclear envelope with molecular masses ranging from 36 to 145 kDa.
- Confirmed the specificity of iodination for nuclear envelope proteins, excluding histones and cytoplasmic contaminants.
Conclusions:
- The described iodination technique is a sensitive and rapid method for nuclear envelope protein identification.
- This method allows for detailed characterization of nuclear envelope protein composition.
- The findings contribute to a better understanding of nuclear envelope structure and function.
Abstract:
A sensitive technique is described for the rapid identification of nuclear-envelope proteins. Mouse liver nuclei (purified on sucrose gradients) were iodinated with Na125I by the immobilized water-insoluble reagent Iodogen. Iodinated nuclei were digested with RNAase A and DNAase I and then salt-extracted to obtain labelled nuclear envelopes. Nuclear envelopes were characterized by morphological and biochemical criteria and by SDS/polyacrylamide-gel electrophoresis. In all, 13 polypeptides of molecular masses 145, 115, 98, 85, 75, 70, 65, 54, 50, 45, 40, 38 and 36 kDa were identified in the labelled nuclear envelopes. The labelled polypeptides were localized to the nuclear envelope by extraction of the envelope with Triton X-100 and different concentrations of salt. Iodination of intact nuclei was shown to be specific for the nuclear envelope by the absence of labelling of histones and cytoplasmic contaminants.
