Cluster of differentiation (CD) 24 or heat stable antigen 24 (HSA) molecule is a mucin-type glycoprotein attached to the cell surface by glycosylphosphatidylinositol (GPI)-anchor, promoting adhesive interactions between cells or in extracellular matrix. The aim of this study was to determine the not yet fully identified porcine CD24 gene and protein structure using computational analysis and to validate variants reported in exons of CD24 gene using direct sequencing. A total of 59 samples belonging to Yorkshire, Landrace, Berkshire, Jeju black pig and wild boar were used in the study. Human CD24 mRNA sequences were used as a reference and subjected to BLAST searches to retrieve the orthologous expressed sequence tags (ESTs) or cDNA sequences against NCBI and Ensemble databases. Assembled ESTs and retrieved cDNA sequences for the porcine CD24 gene were used for specific BLAST search to determine its genomic structure. We found porcine CD24 gene to consist of two exons and a relatively long intron. Second exon of porcine CD24 gene had a long 3’ untranslated region (UTR) and was very similar to that of human, mouse, rat, and sheep. The sequence homology of porcine CD24 protein was 65.38-84.62%, when analyzed with amino acid sequences of rat, mouse, human, cattle, and sheep CD24 protein. N-terminal signal sequence, O-glycosylation sites and GPI-anchoring signal sites were also predicted in pig, which showed these motifs to be evolutionary conserved across the species. Variant analysis in exonic regions of porcine CD24 among the multiple breeds showed that only second exon contained eight SNPs and three insertions in a 3’ UTR. Taken together, this study reports putative porcine CD24 gene and its protein structure using in silico approaches, which will be helpful for any further functional studies.

Introduction
 Materials and Methods
  Porcine CD24 gene identification
  Alignment analysis
  Protein sequence analysis
  CD24 protein structure and ligand interaction analysis
  Regulatory element analysis
  Sequencing and variant analysis
 Results and Discussion
  Structural analysis of porcine CD24 gene
  Alignment analysis
  CD24 protein structure and ligand interaction analysis
  Regulatory element analysis
  Sequencing and variant analysis
 Conclusion
 ORCID
 Reference

• Haesu Ko(National Institute of Animal Science, Rural Development Administration, Department of Animal Biotechnology, Chonbuk National University) Corresponding author
• Han-Ha Chai(National Institute of Animal Science, Rural Development Administration, College of Pharmacy, Chonnam National University)
• Gul-Won Jang(National Institute of Animal Science, Rural Development Administration)
• Jong-Eun Park(National Institute of Animal Science, Rural Development Administration)
• Jun-Mo Kim(National Institute of Animal Science, Rural Development Administration)
• Kyung-Tai Lee(National Institute of Animal Science, Rural Development Administration)