Characterization of the gene for apolipoprotein E5-Frankfurt (Gln81 -> Lys, Cys112 -> Arg) by polymerase chain reaction, restriction isotyping, and temperature gradient gel electrophoresis
✍ Scribed by Viktor Ruzicka; Dr. Winfried Mäz; Andreas Russ; Eva Fisher; Werner Mondorf; Werner Groß
- Book ID
- 102832143
- Publisher
- John Wiley and Sons
- Year
- 1993
- Tongue
- English
- Weight
- 691 KB
- Volume
- 14
- Category
- Article
- ISSN
- 0173-0835
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✦ Synopsis
Abstract
A new apolipoprotein (apo) E variant, apoE5‐Frankfurt, was identified in a 43‐year‐old male with moderate hypercholesterolemia. On isoelectric focusing in an immobilized pH gradient, apoE5‐Frankfurt migrated to a position more cathodic than apoE4 (Cys^112^ ‐> Arg). On sodium dodecyl sulfate‐gel electrophoresis, its apparent molecular weight could not be distinguished from that of the three common apoE isoforms (E2, E3 and E4). Restriction isotyping with __Cfo__I (__Hha__I) showed that apoE5‐Frankfurt had arginine in positions 112 and 158 of the mature protein, suggesting that the mutation accounting for the additional positive charge had occurred in an ϵ4 allele. The third and the fourth exon of the apoE gene were amplified using the polymerase chain reaction and analyzed by temperature gradient gel electrophoresis. This suggested that there were two mutations in the fourth exon of the mutant allele. Cloning and sequencing disclosed that, apart from the exchange of arginine for cysteine in position 112, a C to A substitution replaced glutamine (CAA) in position 81 by lysine (AAA).