title: Cloning and identification of two novel splice variants of human PD-L2.
abstract: PD-L2, a newly identified member of B7 family, plays a role in down-regulating T cell responses. The common PD-L2 mRNA (type I) is the splicing product containing all 6 exons. We report here the identification of two human PD-L2 splice variants in activated leukocytes. One splice variant (type II) is generated through splicing out exon 3 encoding Ig constant-like domain; it retains all other regions without a frame shift. The other variant (type III) is created by splicing out exon 3 to an alternative acceptor site 5 bp downstream of the canonical acceptor site, leading to a frame shift. Consequently, the translated protein should be a soluble form. Furthermore, type I isoform is expressed on the plasma surface whereas type II isoform showed a pattern of intracellular membrane distribution in the transiently transfected K562 cells. In addition, the expression patterns of PD-L2 splice variants are variable in different individuals and distinct cellular status. These results suggest that PD-L2 expression may be controlled by posttranscriptional regulation through alternative splicing, and modulation of PD-L2 isoform expression may influence the outcome of immune response.
authors.affiliation: Key Laboratory of Tissue Transplantation and Immunology, Ji'nan University, Ministry of Education, Guangzhou, China. thexh@jnu.edu.cn
authors.forename: Xian-Hui
authors.initials: XH
authors.lastname: He
authors.forename: Yi
authors.initials: Y
authors.lastname: Liu
authors.forename: Li-Hui
authors.initials: LH
authors.lastname: Xu
authors.forename: Yao-Ying
authors.initials: YY
authors.lastname: Zeng
mesh_terms: D017398:Alternative Splicing; D000595:Amino Acid Sequence; D015703:Antigens, CD; D001483:Base Sequence; D002478:Cells, Cultured; D003001:Cloning, Molecular; D005091:Exons; D015870:Gene Expression; D014644:Genetic Variation; D049452:Green Fluorescent Proteins; D006801:Humans; D036341:Intercellular Signaling Peptides and Proteins; D020014:K562 Cells; D007962:Leukocytes / Q000737:chemistry; D008164:Luminescent Proteins / Q000378:metabolism; D008213:Lymphocyte Activation; D018613:Microscopy, Confocal; D008969:Molecular Sequence Data; D010455:Peptides / Q000235:genetics*; D016133:Polymerase Chain Reaction; D061027:Programmed Cell Death 1 Ligand 2 Protein; D020033:Protein Isoforms / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D021382:Protein Sorting Signals; D017434:Protein Structure, Tertiary; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid
chemical_list: D015703:Antigens, CD; D036341:Intercellular Signaling Peptides and Proteins; D008164:Luminescent Proteins; C556977:PDCD1LG2 protein, human; D010455:Peptides; D061027:Programmed Cell Death 1 Ligand 2 Protein; D020033:Protein Isoforms; D021382:Protein Sorting Signals; D011993:Recombinant Fusion Proteins; D049452:Green Fluorescent Proteins