An acceptor splice site mutation in intron 16 of the low density lipoprotein receptor gene leads to an elongated, internalization defective receptor

An acceptor splice site mutation in intron 16 of the low density lipoprotein receptor gene leads to an elongated, internalization defective receptor

Lombardi, P.
Hoffer, M.J.V.
Top, B.
de Wit, E.
Gevers Leuven, J.A.
Frants, R.R.
Havekes, L.M.
Gaubius Instituut TNO

1993

In this report, we describe the characterization of a mutation in the low density lipoprotein (LDL) receptor gene of a true homozygous familial hypercholesterolemic (FH) patient. The combined use of denaturing gradient gel electrophoresis (DGGE) and DNA sequence analysis revealed a unique A to G transition in the penultimate 3'-nucleotide of intron 16 of the LDL receptor gene, which disrupts the acceptor splice site. cDNA sequence analysis indicated that a cryptic splice site was activated in intron 16, upstream from the original splice site, leading to the inclusion of 62 nucleotides and a reading frame-shift. The resulting new translation product contains a stretch of 154 amino acids at the carboxy-terminal that have no resemblance to the normal receptor protein. To elucidate the biological effects of the mutation, the structural and functional properties of the mutated LDL receptor protein were studied. Immunoprecipitation of the newly synthesized LDL receptors showed that an aberrant precursor form of the LDL receptor protein was synthesized, about 10 kDa larger than normal, which is not further processed to the mature form. Some 50% of the normal LDL binding activity was found on the cell surface of the patient's fibroblasts, whereas internalization and degradation of LDL were abolished. Molecular Sequence Numbers: GENBANK: L06914, L06915, L06916, L06917, L06918, L06919, L22587, L22588, L22589, S70123; Chemicals/CAS: Receptors, LDL

Denaturating gradient gel electrophoresis
Polymerase chain reaction
Complementary dna
Low density lipoprotein receptor
Case report
Dna sequence
Familial hypercholesterolemia
Gel electrophoresis
Mutation
Pedigree analysis
Polymerase chain reaction
Adult
Amino Acid Sequence
Base Sequence
Cells, Cultured
Electrophoresis
Female
Homozygote
Human
Hypercholesterolemia, Familial
Introns
Molecular Sequence Data
Pedigree
Point Mutation
Reading Frames
Receptors, LDL
RNA Splicing
Sequence Analysis, DNA
Support, Non-U.S. Gov't

http://resolver.tudelft.nl/uuid:8adddb54-03b7-40bd-bc6b-e914e23330ab

232339

0021-9150

Atherosclerosis, 104 (1-2), 117-128

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