A Natural Disruption of the Secretory Group II Phospholipase A2 Gene in Inbred Mouse Strains (*)
- Brian P. Kennedy(1)(§),
- Paul Payette(1),
- John Mudgett(2),
- Peter Vadas(3),
- Waldemar Pruzanski(3),
- Mei Kwan(1),
- Clementine Tang(1),
- Derrick E. Rancourt(4) and
- Wanda A. Cromlish(1)
- From the (1) Department of Biochemistry and Molecular Biology, Merck Frosst Center for Therapeutic Research, Pointe Claire-Dorval, Quebec H9R 4P8, Canada, the
- (2) Department of Molecular Immunology, Merck Research Laboratories, Rahway, New Jersey 07065-0900, the
- (3) Inflammation Research Group, The Wellesley Hospital, University of Toronto, Toronto, Ontario M4Y 1J3, Canada, and the
- (4) Howard Hughes Medical Institute, University of Utah, Salt Lake City, Utah 84112
- § To whom correspondence should be addressed: Dept. of Biochemistry and Molecular Biology, Merck Frosst Center for Therapeutic Research, Merck Frosst Canada Inc., P.O. Box 1005, Pointe Claire-Dorval, Quebec H9R 4P8, Canada . Tel.: 514-428-8548; Fax: 514-428-8615.
Abstract
The synovial fluid or group II secretory phospholipase A
(sPLA
) has been implicated as an important agent involved in a number of inflammatory processes. In an attempt to determine the
role of sPLA
in inflammation, we set out to generate sPLA
-deficient mice. During this investigation, we observed that in a number of inbred mouse strains, the sPLA
gene was already disrupted by a frameshift mutation in exon 3. This mutation, a T insertion at position 166 from the ATG
of the cDNA, terminates out of frame in exon 4, resulting in the disruption of the calcium binding domain in exon 3 and loss
of both activity domains coded by exons 4 and 5. The mouse strains C57BL/6, 129/Sv, and B10.RIII were found to be homozygous
for the defective sPLA
gene, whereas outbred CD-1:SW mice had variable genotype at this locus. BALB/c, C3H/HE, DBA/1, DBA/2, NZB/B1N, and MRL lpr/lpr mice had a normal sPLA
genotype. The sPLA
mRNA was expressed at very high levels in the BALB/c mouse small intestine, whereas in the small intestine of the sPLA
mutant mouse strains, sPLA
mRNA was undetectable. In addition, PLA
activity in acid extracts of the small intestine were approximately 40 times higher in BALB/c than in the mutant mice. Transcription
of the mutant sPLA
gene resulted in multiple transcripts due to exon skipping. None of the resulting mutant mRNAs encoded an active product.
The identification of this mutation should not only help define the physiological role of sPLA
but also has important implications in mouse inflammatory models developed by targeted mutagenesis.
Footnotes
-
↵* This work was supported in part by a Medical Research Council/Pharmaceutical Manufacturer Association of Canada health program grant. The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore by hereby marked “advertisement” in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.
The nucleotide sequence(s) reported in this paper has been submitted to the GenBank™/EMBL Data Bank with accession number(s) U32313[GenBank], U32358[GenBank], and U32359[GenBank].
-
↵1 The abbreviations used are:
- sPLA
-
synovial fluid or group II secretory phospholipase A
- PLA
-
phospholipase A
- bp
-
base pair(s)
- PCR
-
polymerase chain reaction
- RT-PCR
-
reverse transcriptase-PCR
- kb
-
kilobase pair(s)
- LPS
-
lipopolysaccharide
- PBS
-
phosphate-buffered saline.
- sPLA
-
- Received June 15, 1995.
- Revision received July 13, 1995.
- © 1995 by The American Society for Biochemistry and Molecular Biology, Inc.
