title: Differential effects of overexpression of two forms of ephrin-A5 on neonatal rat cardiomyocytes.
abstract: Eph receptors constitute the largest family of receptor tyrosine kinases. Multiple transcripts of ephrin-A5, the cognate ligand of the EphA3 receptor, were found in neonatal rat cardiomyocytes. Two cDNA clones encoding the full-length ephrin-A5 (ephrin-A5 alpha) and a 27-amino acid deletion form (ephrin-A5 beta) were isolated. To examine the role of ephrin-A5 in cardiomyocytes, the cDNAs were inserted into adenoviral vectors, termed Ad.ephrin-A5 alpha and Ad.ephrin-A5 beta, respectively, and overexpressed in cardiomyocytes. The effect of ephrin-A5 on cardiomyocyte gene expression was investigated using a cDNA expression array and Western blot analysis. The results showed that both ephrin-A5 alpha and ephrin-A5 beta downregulated cyclin D2, cyclin-dependent kinase-4 proteins, and their cognate receptor EphA3, which were associated with reduced bromodeoxyuridine incorporation in cardiomyocytes. Whereas ephrin-A5 alpha and ephrin-A5 beta also induced differential gene expression, only ephrin-A5 beta significantly upregulated the transcription of brain natriuretic peptide and downregulated ras-related protein RAB2, protein kinase C inhibitor protein-1, clusterin, and insulin-like growth factor-binding protein. The results suggest that the two forms of ephrin-A5 share similar function while differ in regulating different sets of genes in cardiomyocytes.
authors.affiliation: Cardiovascular Institute, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15213, USA. liyuny@pitt.edu
authors.forename: Y Y
authors.initials: YY
authors.lastname: Li
authors.forename: Z
authors.initials: Z
authors.lastname: Mi
authors.forename: Y
authors.initials: Y
authors.lastname: Feng
authors.forename: C F
authors.initials: CF
authors.lastname: McTiernan
authors.forename: R
authors.initials: R
authors.lastname: Zhou
authors.forename: P D
authors.initials: PD
authors.lastname: Robbins
authors.forename: S C
authors.initials: SC
authors.lastname: Watkins
authors.forename: A M
authors.initials: AM
authors.lastname: Feldman
mesh_terms: D000256:Adenoviridae / Q000235:genetics; D000595:Amino Acid Sequence; D000818:Animals; D000831:Animals, Newborn; D001483:Base Sequence; D002478:Cells, Cultured; D056742:Cyclin D2; D051358:Cyclin-Dependent Kinase 4; D018844:Cyclin-Dependent Kinases / Q000235:genetics; D016213:Cyclins / Q000235:genetics; D004247:DNA / Q000096:biosynthesis; D015536:Down-Regulation / Q000235:genetics; D036384:Ephrin-A3; D036386:Ephrin-A5; D018507:Gene Expression Regulation, Developmental / Q000502:physiology; D018014:Gene Transfer Techniques; D008565:Membrane Proteins / Q000235:genetics*; D008969:Molecular Sequence Data; D018485:Muscle Fibers, Skeletal / Q000166:cytology / Q000502:physiology*; D009206:Myocardium / Q000166:cytology*; D020411:Oligonucleotide Array Sequence Analysis; D011518:Proto-Oncogene Proteins; D051381:Rats; D017207:Rats, Sprague-Dawley; D014158:Transcription, Genetic / Q000502:physiology
chemical_list: C486197:Ccnd2 protein, rat; D056742:Cyclin D2; D016213:Cyclins; D036384:Ephrin-A3; D036386:Ephrin-A5; D008565:Membrane Proteins; D011518:Proto-Oncogene Proteins; D004247:DNA; C495903:Cdk4 protein, rat; D051358:Cyclin-Dependent Kinase 4; D018844:Cyclin-Dependent Kinases