Identification and distribution of a novel platelet-derived growth factor receptor beta variant: effect of retinoic acid and involvement in cell differentiation.
We have shown previously that neonatal testicular gonocytes express platelet-derived growth factor receptors (PDGFR) alpha and beta. We report the expression of a novel PDGFRbeta (V1-PDGFRbeta) transcript in gonocytes of 3-d-old rat testes. V1-PDGFRbeta nucleotide sequence spans from intron 6 to exon 23 of the PDGFRbeta gene, and is predicted to encode a protein lacking part of the extracellular domain. V1-PDGFRbeta transcripts are expressed preferentially in developing gonads. The embryonic teratocarcinoma F9 cells, in which differentiation is driven by retinoic acid (RA), express V1-PDGFRbeta, but not wild-type PDGFRbeta. Green fluorescent protein-tagged V1-PDGFRbeta localized mainly in cytosol of F9, MA-10, and COS-1 cells. FLAG and green fluorescent protein-tagged V1-PDGFRbeta displayed tyrosine kinase activities and contain phosphotyrosine residues, suggesting that V1-PDGFRbeta is a cytosolic tyrosine kinase. Treatment of F9 cells with RA induced V1-PDGFRbeta gene expression, concomitant with changes in morphology and increased mRNA expression of collagen IV and laminin B1, suggesting that V1-PFGRbeta is involved in cell differentiation. Similarly, treatment of postnatal d 3 rat gonocytes with RA induced a dose-dependent increase in V1-PDGFRbeta expression together with an increase in c-kit and Stra8, markers of more differentiated germ cells and a concomitant decrease in GFRalpha1, a marker of spermatogonial stem cells. However, an excess of V1-PDGFRbeta inhibited RA-mediated collagen IV and laminin B1 expression and altered both RA-dependent and RA-independent morphological changes in F9 cells, while increasing cell survival. These results suggest that the expression of V1-PDGFRbeta is tightly regulated during differentiation and that it may play an active role in germ cell differentiation.
Wang
Yan
Y
Department of Biochemistry and Molecular and Cellular Biology, Georgetown University Medical Center, Washington, D.C. 20057, USA.
Culty
Martine
M
D016475:3T3 Cells; D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology*; D001943:Breast Neoplasms; D019556:COS Cells; D002454:Cell Differentiation / Q000187:drug effects / Q000502:physiology; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects / Q000502:physiology; D002522:Chlorocebus aethiops; D005260:Female; D014644:Genetic Variation; D005854:Germ Cells / Q000166:cytology / Q000502:physiology*; D005910:Glioma; D049452:Green Fluorescent Proteins / Q000235:genetics; D006801:Humans; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D011247:Pregnancy; D011505:Protein-Tyrosine Kinases / Q000235:genetics / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D020797:Receptor, Platelet-Derived Growth Factor beta / Q000235:genetics* / Q000378:metabolism; D018243:Teratocarcinoma; D013737:Testis / Q000166:cytology; D014212:Tretinoin / Q000494:pharmacology*
D000970:Antineoplastic Agents; C485192:green fluorescent protein, Aequorea victoria; D049452:Green Fluorescent Proteins; D014212:Tretinoin; D011505:Protein-Tyrosine Kinases; D020797:Receptor, Platelet-Derived Growth Factor beta