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Secondary structure for the apolipoprotein B mRNA editing site. Au-binding proteins interact with a stem loop
N Richardson1, N Navaratnam, J Scott
1MRC Molecular Medicine Group, Clinical Science Centre, Imperial College School of Medicine, Hammersmith Hospital, Du Cane Road, London W12 0NN, United Kingdom.
The Journal of Biological Chemistry
|November 21, 1998
Summary
Researchers identified auxiliary proteins (p43/45) crucial for apolipoprotein B (apoB) mRNA editing. These proteins bind to specific RNA structures, facilitating the conversion of C to U, which generates apoB48.
Area of Science:
- Biochemistry
- Molecular Biology
- Genetics
Background:
- Apolipoprotein B (apoB) mRNA undergoes C to U editing, converting a glutamine codon to a stop codon, producing apoB48.
- The catalytic subunit APOBEC-1 requires auxiliary factors for efficient apoB mRNA editing.
Purpose of the Study:
- To investigate the structural elements of apoB mRNA involved in editing.
- To identify and characterize auxiliary factors that participate in apoB mRNA editing.
Main Methods:
- Computer modeling and ribonuclease probing were used to analyze apoB RNA structure.
- Proteins from chick enterocytes were identified and their RNA binding properties were assessed.
Main Results:
- A stem-loop structure at the editing site of apoB mRNA was identified, containing essential sequence motifs.
- 43/45 kDa proteins (p43/45) were identified as potential auxiliary editing factors.
- p43/45 proteins exhibit preferential binding to AU-rich RNA and the specific loop motif of apoB mRNA.
Conclusions:
- The identified stem-loop structure likely presents the target cytidine for APOBEC-1 deamination.
- The p43/45 proteins are implicated as auxiliary factors in apoB mRNA editing due to their binding characteristics.