Thermal Stability of Apolipoprotein B100 in Low-Density Lipoprotein Is Disrupted at Early Stages of Oxidation While Neutral Lipid Core Organization Is Conserved†

Biochemistry ◽  
1998 ◽  
Vol 37 (3) ◽  
pp. 938-944 ◽  
Author(s):  
Ruth Prassl ◽  
Bernhard Schuster ◽  
Peter Laggner ◽  
Claudie Flamant ◽  
Fabienne Nigon ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Neutral Lipid ◽  
Low Density Lipoprotein ◽  
Density Lipoprotein ◽  
Low Density ◽  
Lipid Core ◽  
Early Stages ◽  
Apolipoprotein B100 ◽  
Thermal Stability Of

Structural Basis for Thermal Stability of Human Low-Density Lipoprotein†

Biochemistry ◽  
2005 ◽  
Vol 44 (10) ◽  
pp. 3965-3971 ◽  
Author(s):  
Shobini Jayaraman ◽  
Donald Gantz ◽  
Olga Gursky
Keyword(s):  
Thermal Stability ◽  
Low Density Lipoprotein ◽  
Density Lipoprotein ◽  
Structural Basis ◽  
Low Density ◽  
Thermal Stability Of

Transcriptional regulation of the apolipoprotein B100 gene: purification and characterization of trans-acting factor BRF-2

1992 ◽  
Vol 12 (7) ◽  
pp. 3183-3191
Author(s):  
H Zhuang ◽  
S S Chuang ◽  
H K Das
Keyword(s):  
Low Density Lipoprotein ◽  
Density Lipoprotein ◽  
Low Density ◽  
Hypersensitive Site ◽  
Apob Gene ◽  
Mobility Shift ◽  
Gel Mobility Shift Assay ◽  
Apolipoprotein B100 ◽  
Mobility Shift Assay ◽  
Gel Mobility Shift

Apolipoprotein B100 (apoB), the only protein of low-density lipoprotein, is produced primarily in the liver and serves as a ligand for the low-density lipoprotein receptor. Hepatic cell-specific expression of the human apoB gene is controlled by at least two cis-acting positive elements located between positions-128 and -70 (H. K. Das, T. Leff, and J.L. Breslow, J. Biol. Chem. 263:11452-11458, 1988). The distal element (-128 to -85) appears to be liver specific since it shows positive activity in HepG2 cells and negative activity in HeLa cells. The proximal element (-84 to -70) acts as a positive element in both these cell lines, and two rat liver nuclear proteins, BRF-1 and C/EBP, bind to two overlapping sites (-84 to -60 and -70 to -50, respectively). By gel mobility shift assay, we have identified a rat liver nuclear protein (BRF-2) which binds to the distal element (-128 to -85) of the apoB gene. This putative trans-acting factor has been purified to apparent homogeneity by DEAE-cellulose, heparin-agarose, and DNA-specific affinity chromatography. The purified BRF-2 has an apparent molecular mass of 120 kDa and was found to specifically recognize sequence -128 to -85; BRF-2 also produced a strong hypersensitive site at nucleotide position -95 with copper-orthophenanthroline reagent. A double-stranded oligonucleotide (-128 to -85) containing a 3-nucleotide (TTC) insertion between position -95 and -94 was found to abolish DNA binding by BRF-2. This result suggests that the region surrounding the hypersensitive site -95 is important for protein-DNA interaction. By using apoB promoter fragments containing various internal deletions as templates for gel mobility shift assay, the region between -104 and -85 was identified to be crucial for binding by BRF-2. We propose that BRF-2 may play an important role in the tissue-specific regulation of apoB gene transcription.

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