Identification and characterization of a new human gene (APOC4) in the apolipoprotein E, C-I, and C-II gene locus
- Univ. of California, San Francisco, CA (United States)
- UAB Medical Center, Birmingham, AL (United States)
We have identified and characterized a previously unreported human gene that is found within the apolipoprotein (apo) E/C-I/C-II gene locus. On the basis of its location and its properties, this new gene has been designated APOC4. Nucleotide sequence analysis of genomic DNA and liver cDNA clones revealed a 3.3-kb gene consisting of three exons and two introns. Its 3{prime} terminus lies 555 bp upstream of APOC2, giving both genes the same transcriptional orientation. The promoter of the APOC4 gene lacks a typical TATA box, consistent with an apparent heterogeneity in transcription start sites. RNase protection analysis indicated relatively low apoC-IV mRNA levels in human liver, compared to apoC-II mRNA levels. The predicted apoC-IV protein sequence, comprising 127 amino acid residues, contains a putative 25-residue signal peptide and two potential amphipathic {alpha}-helical domains. Amino acid sequence comparisons indicate a limited homology between apoC-IV and either apoC-I or apoC-II. Since its hepatic expression and predicted protein structure are characteristic of the other genes in this cluster, we propose that the APOC4 gene is a member of the apolipoprotein gene family. 53 refs., 6 figs.
- OSTI ID:
- 390934
- Journal Information:
- Genomics, Journal Name: Genomics Journal Issue: 2 Vol. 28; ISSN GNMCEP; ISSN 0888-7543
- Country of Publication:
- United States
- Language:
- English
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