Putative alternative trans-splicing of leukocyte adhesion-GPCR pre-mRNAs generates functional chimeric receptors.
The EGF-TM7 receptors, a subfamily of adhesion-GPCRs mostly restricted to leukocytes, are known to express multiple functional protein isoforms through extensive alternative cis-splicing. Here, we demonstrate that EGF-TM7 pre-mRNAs also undergo the rare trans-splicing, leading to the generation of functional chimeric receptors. RT-PCR and in silico analyses of EMR2 transcripts identified unique fragments containing the EGF-like motif 3 of a closely related EGF-TM7 gene, CD97, in addition to the alternative cis-spliced products. The sequence swapping is restricted to the EGF-3 exon, generating unique EMR2(1-2-3*-5) and EMR2(1-2-3*-4-5) molecules, which are functional in ligand-binding as the wild-type EMR2(1-2-3-4-5) and CD97(1-2-3-4-5) receptors. Our results suggest that human leukocytes employ trans-splicing as well as cis-splicing to increase the repertoire of functional adhesion-GPCRs.
Chiu
Pei-Ling
PL
Department of Medical Biotechnology and Laboratory Science, College of Medicine, Chang Gung University, Kwei-San, Tao-Yuan, Taiwan.
Ng
Boon Han
BH
Chang
Gin-Wen
GW
Gordon
Siamon
S
Lin
Hsi-Hsien
HH
D017398:Alternative Splicing / Q000235:genetics*; D015703:Antigens, CD / Q000235:genetics*; D001483:Base Sequence; D002460:Cell Line; D002999:Clone Cells; D019295:Computational Biology; D005091:Exons / Q000235:genetics; D020224:Expressed Sequence Tags; D006801:Humans; D007438:Introns / Q000235:genetics; D008024:Ligands; D008562:Membrane Glycoproteins / Q000235:genetics*; D008969:Molecular Sequence Data; D020033:Protein Isoforms / Q000235:genetics; D012322:RNA Precursors / Q000235:genetics*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D043562:Receptors, G-Protein-Coupled / Q000235:genetics*; D016028:Receptors, Leukocyte-Adhesion / Q000235:genetics*; D020133:Reverse Transcriptase Polymerase Chain Reaction
C412456:ADGRE2 protein, human; C095004:ADGRE5 protein, human; D015703:Antigens, CD; D008024:Ligands; D008562:Membrane Glycoproteins; D020033:Protein Isoforms; D012322:RNA Precursors; D012333:RNA, Messenger; D043562:Receptors, G-Protein-Coupled; D016028:Receptors, Leukocyte-Adhesion