Programmed cell death 1 pre-mRNA exon 3 exonic splicing enhancer sequence (PD-1 exon 3 ESE)

The Programmed cell death 1 (PD-1) pre-mRNA exon 3 exonic splicing enhancer (ESE) sequence is a specific regulatory region within the PDCD1 transcript that governs the inclusion of the exon encoding the protein's transmembrane domain. PD-1 is a key inhibitory receptor expressed on T cells that maintains immune homeostasis but is often exploited by tumors to evade immune surveillance (Nielsen et al., 2005, Cellular Immunology). The ESE sequence serves as a binding site for splicing factors that recruit the spliceosome to ensure exon 3 is retained in the mature mRNA. Therapeutic targeting of this sequence using splice-switching oligonucleotides (SSOs) prevents the inclusion of exon 3, resulting in the production of a soluble PD-1 (sPD-1) isoform (Wan et al., 2006, Journal of Immunology). This soluble variant lacks the transmembrane anchor and can function as a competitive antagonist, sequestering PD-L1 and PD-L2 ligands and thereby restoring T-cell mediated anti-tumor activity (Zhou et al., 2013, Cancer Gene Therapy). This genetic modulation strategy offers a potential alternative to traditional monoclonal antibody-based checkpoint inhibitors by utilizing the body's own protein synthesis machinery to produce therapeutic decoys.

Other names

PDCD1 exon 3 ESEPD-1 pre-mRNA splicing regulatory elementExon 3 splicing enhancer of PDCD1PD-1 delta ex3 ESE

Steric blocking of the splicing machinery at the exonic splicing enhancer site to induce exon 3 skipping, resulting in the production of soluble PD-1 (sPD-1) instead of membrane-bound PD-1.