title: Synergistic upregulation of erythropoietin receptor (EPO-R) expression by sense and antisense EPO-R transcripts in the canine lung.
abstract: We previously found increased erythropoietin receptor (EPO-R) protein levels in vigorously growing canine lungs after pneumonectomy (PNX), suggesting a role for paracrine EPO signaling in lung growth and remodeling. Now we find that sense and antisense EPO-R transcripts (sEPO-R and asEPO-R, respectively) are concordantly up-regulated in the post-PNX remaining lung, leading to the hypothesis that sEPO-R and asEPO-R interactions enhance EPO signaling during lung growth. We cloned a canine asEPO-R cDNA, which is fully complementary to the sense strand of the EPO-R gene from 2.5kb 3' to the sense stop codon, and extends into the 5' UTR of the sEPO-R transcript. Both asEPO-R and sEPO-R transcripts colocalize with EPO-R protein in the same lung cells. In cultured human embryonic kidney (HEK293) cells, transfection with sEPO-R (+FLAG tag) cDNA alone increased EPO-R protein expression (anti-EPO-R and anti-FLAG). At constant sEPO-R cDNA levels, cotransfection with escalating asEPO-R cDNA further increased recombinant EPO-R protein expression. The asEPO-R transcript harbors two putative opening reading frames (ORFs). Separate transfection of each asEPO-R ORF cDNA resulted in differential stimulatory effects on EPO-R protein expression. We conclude that both sEPO-R and asEPO-R transcripts contribute to in vivo up-regulation of EPO-R protein expression in the post-PNX remaining lung. This demonstrates synergism between sense-antisense EPO-R transcripts in response to physiological stimulation in a robust model of induced lung growth.
authors.affiliation: Departments of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390-9034, USA.
authors.forename: Quiyang
authors.initials: Q
authors.lastname: Zhang
authors.forename: Jianning
authors.initials: J
authors.lastname: Zhang
authors.forename: Orson W
authors.initials: OW
authors.lastname: Moe
authors.forename: Connie C W
authors.initials: CC
authors.lastname: Hsia
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002460:Cell Line; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000235:genetics; D004285:Dogs; D006801:Humans; D008168:Lung / Q000737:chemistry / Q000254:growth & development* / Q000378:metabolism; D008969:Molecular Sequence Data; D016366:Open Reading Frames; D014176:Protein Biosynthesis / Q000235:genetics; D016372:RNA, Antisense / Q000378:metabolism*; D012333:RNA, Messenger / Q000032:analysis / Q000378:metabolism*; D017467:Receptors, Erythropoietin / Q000032:analysis / Q000096:biosynthesis* / Q000235:genetics; D014158:Transcription, Genetic; D015854:Up-Regulation
chemical_list: D018076:DNA, Complementary; D016372:RNA, Antisense; D012333:RNA, Messenger; D017467:Receptors, Erythropoietin