Isolation and sequence of a human apolipoprotein CII cDNA clone and its use to isolate and map to human chromosome 19 the gene for apolipoprotein CII.

Abstract

C[complementary]DNA clones encoding human apolipoprotein CII (apo CII) were identified by screening an adult human liver cDNA library with a mixed oligonucleotide probe corresponding to all possible codons for apo CII amino acid 6-10. One clone with an .apprxeq. 500-base-pair (bp) insert, designated pCII-711, was selected for DNA sequence analysis. This clone contained a DNA sequence that corresponded with the previously reported amino acid sequence of apo CII with only minor differences. The DNA sequence specified a polypeptide of 79 amino acids, compared to the 78 amino acids previously reported. The pCII-711 clone contains a 36-bp DNA sequence upstream from that specifying the NH2-terminal threonine which, when read in frame, specifies the amino acid sequence Leu-Val-Leu-Leu-Val-Leu-Gly-Phe-Glu-Val-Gln-Gly and may be part of an apo CII signal peptide. The pCII-711 clone also contains a 144-bp region that corresponds to the 3'' untranslated region of apo CII mRNA as well as a portion of the poly(A) tail. Clone pCII-711 was used to isolate and characterize by restriction endonuclease digestion the gene for apo CII from a human genomic library. Through Southern blot analysis of DNA from human-rodent somatic cell hybrids, clone pCII-711 also was used to provisionally map the gene for apo CII to human chromosome 19.