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Published on: May 2, 2018
Identification of two transcripts of canine, feline, and porcine interleukin-1 alpha
A F Straubinger1, M M Viveiros, R K Straubinger
1James A. Baker Institute for Animal Health, College of Veterinary Medicine, Cornell University, Ithaca, NY 14853, USA. as34@cornell.edu
Insights
Researchers discovered two forms of interleukin-1alpha (IL-1alpha) mRNA in dogs and cats. The shorter form, lacking a key sequence, was absent in horses and cows, but present in synovial membranes during Borrelia burgdorferi infection.
Area of Science:
- Immunology
- Molecular Biology
- Veterinary Medicine
Background:
- Interleukin-1alpha (IL-1alpha) is a crucial cytokine involved in immune responses.
- Differential gene expression can lead to distinct protein isoforms with varying functions.
- Understanding IL-1alpha transcript variations is important for studying inflammatory diseases.
Purpose of the Study:
- To investigate the molecular characteristics of IL-1alpha transcripts in macrophages.
- To determine the species-specific expression patterns of IL-1alpha mRNA.
- To examine the regulation of IL-1alpha expression in response to bacterial infection.
Main Methods:
- Reverse transcription-polymerase chain reaction (RT-PCR) was used to amplify IL-1alpha cDNA.
- Cloning and sequencing identified differences between transcript variants.
- Southern and Northern blot hybridization assessed mRNA expression across species.
Main Results:
- Two distinct IL-1alpha cDNA fragments were amplified from LPS-stimulated canine and feline macrophages.
- A shorter transcript, lacking a 174-nucleotide sequence (exon 5), was identified.
- This shorter transcript was present in dogs, cats, and pigs, but absent in equine and bovine macrophages.
Conclusions:
- The identified 174-nucleotide deletion in IL-1alpha mRNA affects a calpain cleavage site, potentially impacting protein maturation.
- Species-specific expression of IL-1alpha mRNA variants exists, with implications for inflammatory responses.
- Canine IL-1alpha transcripts are expressed in synovial membranes and upregulated during Borrelia burgdorferi infection.
Abstract:
Reverse transcription-polymerase chain reaction (RT-PCR) with interleukin-1alpha (IL-1alpha)-specific primers using total RNA from lipopolysaccharide (LPS)-stimulated lung macrophages resulted in the amplification of two distinct cDNA fragments. Cloning and sequencing of the canine and feline fragments revealed that, except for the absence of a specific 174 nucleotide sequence, the short and the long transcripts were identical. The in-frame 174 nucleotide deletion corresponds to exon 5 of the human and murine IL-1alpha gene, which encodes the cleavage site for calpain, a protein necessary for the processing of the IL-1alpha precursor into mature IL-1alpha. The two transcripts were found in the dog, cat and pig; analysis by RT-PCR, Southern and Northern blot hybridization showed no expression of the shorter IL-1alpha mRNA in equine or bovine macrophages. Expression of the two canine IL-1alpha transcripts was also detected in synovial membranes and was coordinately up-regulated in response to Borrelia burgdorferi infection under both in-vitro and in-vivo conditions.
