Pla2g12b and Hpn are genes identified by mouse ENU mutagenesis that affect HDL cholesterol.
Despite considerable progress understanding genes that affect the HDL particle, its function, and cholesterol content, genes identified to date explain only a small percentage of the genetic variation. We used N-ethyl-N-nitrosourea mutagenesis in mice to discover novel genes that affect HDL cholesterol levels. Two mutant lines (Hlb218 and Hlb320) with low HDL cholesterol levels were established. Causal mutations in these lines were mapped using linkage analysis: for line Hlb218 within a 12 Mbp region on Chr 10; and for line Hlb320 within a 21 Mbp region on Chr 7. High-throughput sequencing of Hlb218 liver RNA identified a mutation in Pla2g12b. The transition of G to A leads to a cysteine to tyrosine change and most likely causes a loss of a disulfide bridge. Microarray analysis of Hlb320 liver RNA showed a 7-fold downregulation of Hpn; sequencing identified a mutation in the 3' splice site of exon 8. Northern blot confirmed lower mRNA expression level in Hlb320 and did not show a difference in splicing, suggesting that the mutation only affects the splicing rate. In addition to affecting HDL cholesterol, the mutated genes also lead to reduction in serum non-HDL cholesterol and triglyceride levels. Despite low HDL cholesterol levels, the mice from both mutant lines show similar atherosclerotic lesion sizes compared to control mice. These new mutant mouse models are valuable tools to further study the role of these genes, their affect on HDL cholesterol levels, and metabolism.
The Jackson Laboratory, Bar Harbor, Maine, United States of America.
Aleksandra
A
Aljakna
Seungbum
S
Choi
Holly
H
Savage
Rachael
R
Hageman Blair
Tongjun
T
Gu
Karen L
KL
Svenson
Gary A
GA
Churchill
Matt
M
Hibbs
Ron
R
Korstanje
D000469:Alkaline Phosphatase / Q000097:blood; D000704:Analysis of Variance; D000818:Animals; D016375:Antisense Elements (Genetics) / Q000235:genetics; D015152:Blotting, Northern; D015153:Blotting, Western; D008076:Cholesterol, HDL / Q000378:metabolism*; D002874:Chromosome Mapping; D003433:Crosses, Genetic; D005038:Ethylnitrosourea; D016057:Evoked Potentials, Auditory, Brain Stem; D014644:Genetic Variation; D059014:High-Throughput Nucleotide Sequencing; D008055:Lipids / Q000097:blood; D008126:Lod Score; D051379:Mice; D008810:Mice, Inbred C57BL; D046228:Microarray Analysis; D023421:Models, Animal; D016296:Mutagenesis / Q000235:genetics; D054467:Phospholipases A2 / Q000235:genetics*; D012697:Serine Endopeptidases / Q000235:genetics*; D013045:Species Specificity; D013974:Thyroxine / Q000097:blood
D016375:Antisense Elements (Genetics); D008076:Cholesterol, HDL; D008055:Lipids; D054467:Phospholipases A2; D000469:Alkaline Phosphatase; D012697:Serine Endopeptidases; C055645:hepsin; D005038:Ethylnitrosourea; D013974:Thyroxine