PG-4

Whole-Genome Analysis Reveals the Probable Donor Cat Phenotype of PG-4 Astrocyte Cells

Crandell-Rees Feline Kidney (CRFK) and PG-4 cells are long-established cell lines with undocumented donor origins. Whole-genome sequencing of PG-4 cells identified specific genetic variants linked to coat and iris color. Key findings include a homozygous deletion in the ASIP gene, a compound heterozygous mutation in FGF5 (c.474delT and c.475A>C; Fig. 1), heterozygous mutations in LVRN (c.416C>A and c.2522G>A), and a heterozygous Siamese-color allele in TYR (c.904G>A). No large deletions were found in the KIT-KDR intergenic region or ARHGAP36intron 1 (Fig. 2).

Long-read sequencing revealed that six reads mapped to the KIT-FERV1 locus, with four containing a >7 kbp insertion of the FERV1 homolog (Fig. 3), indicating a heterozygous insertion. While the TYR mutation is recessive and masked by ASIP, the FERV1 insertion is dominant and the FGF5 compound heterozygote causes long fur. Consequently, the PG-4 donor cat likely had white spotting (white and black), unstriped, long fur. The absence of FERV1-LTR or RD114-LTR insertions in PAX3 intron 4 suggests the donor had non-blue irises. These results reconstruct the probable phenotype of the PG-4 donor and highlight the utility of genomic analysis in characterizing historical cell lines.