The number of kringle IV repeats 3-10 is invariable in the human apo(a) gene.
The human apolipoprotein(a) (apo(a)) gene is a member of a family of related genes including plasminogen, apo(a)rg-B and apo(a)rg-C, which are clustered on chromosome 6q 2,7. Apo(a) contains ten different types of plasminogen-like kringle IV repeats (K-IV 1-10) one of which (K-IV 2) varies in number resulting in a remarkable size polymorphism of the protein. Sequence analysis of human apo(a) alleles and indirect evidence have suggested that K-IV 1 and K-IV 3-10 are each present once in individual alleles and that the 3' apo(a) region encompassing kringles IV 3-10, kringle V and the protease domain is invariable. To directly test this, we have constructed a restriction map of the apo(a) gene region from genomic DNA and from a yeast artificial chromosome (YAC) (K-IV 13) which contains the entire apo(a) gene. The presence of a 63 kb ClaI fragment encompassing kringles IV 3-10, kringle V and the protease domain and a 46 kb SwaI fragment, spanning kringles IV 5-10, kringle V and the protease domain was demonstrated by PFGE/Southern blotting in 30 unrelated subjects, who represented a range of apo(a) size alleles containing from 11 to 49 kringles. Our analysis demonstrates that the number of kringles IV 3-10 is invariable in the human apo(a) gene, suggesting that the 3'domain of Apo(a) is functionally important.
Haibach
C
C
Institute for Medical Biology and Human Genetics, University of Innsbruck, Austria.
Kraft
H G
HG
Köchl
S
S
Abe
A
A
Utermann
G
G
D001053:Apolipoproteins / Q000737:chemistry* / Q000235:genetics*; D053241:Apoprotein(a); D001483:Base Sequence; D002874:Chromosome Mapping; D018244:Chromosomes, Artificial, Yeast; D002896:Chromosomes, Human, Pair 6; D004247:DNA / Q000097:blood; D017931:DNA Primers; D014644:Genetic Variation; D006801:Humans; D017270:Lipoprotein(a); D005810:Multigene Family; D015345:Oligonucleotide Probes; D011110:Polymorphism, Genetic; D012150:Polymorphism, Restriction Fragment Length; D015183:Restriction Mapping
D001053:Apolipoproteins; D017931:DNA Primers; D017270:Lipoprotein(a); D015345:Oligonucleotide Probes; D004247:DNA; D053241:Apoprotein(a)