There are two copies of the human apolipoprotein C-1 gene linked closely downstream from the apolipoprotein E. gene
An apolipoprotein (apo-) C-I cDNA was used to select from a human genomic library a cosmid clone that contained the entire apo-C-I gene. The gene for apo-C-I was found to be 5.5 kb downstream from the gene for apo-E, and a copy of the apo-C-I gene, termed apo-C-I', was found 7.5 kb downstream from the first apo-C-I gene. Both of these apo-C-I genes have been sequenced. Each contains four exons and three introns in similar locations and thus are structurally similar to other apolipoprotein genes. The second and third introns consist mainly of Alu family sequences; some of these sequences are found in both of the genes, whereas others are found in only one. The apo-C-I gene closest to the apo-E gene encodes the known apo-C-I plasma protein. The second apo-C-I gene varies from the first in 9% of the exonic bases; one of these mutations, in the third exon, introduces a translational stop site. Gene-specific probes detected no mRNA from the second gene in human liver, suggesting that the apo-C-I' gene may be a pseudo-gene. The upstream apo-C-I gene is expressed primarily in the liver, while the closely linked apo-E gene is expressed in a wide variety of tissues. As with apo-E, the gene for apo-C-I is activated when monocytes differentiate into macrophages, which may account for the presence of low levels of apo-C-I in such tissues as lung and spleen.
- Research Organization:
- Univ. of California, San Francisco
- OSTI ID:
- 6174171
- Report Number(s):
- CONF-870644-
- Journal Information:
- Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States), Journal Name: Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States) Vol. 46:6; ISSN FEPRA
- Country of Publication:
- United States
- Language:
- English
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