title: Development-related splicing regulates pituitary adenylate cyclase-activating polypeptide (PACAP) receptors in the retina.
abstract: OBJECTIVE
  The ubiquitous pituitary adenylate cyclase-activating peptide (PACAP) has a disparate array of functions in development (e.g., proliferation and apoptosis). Among three types of PACAP receptor (VPAC1, VPAC2, and PAC1), PAC1 is subject to alternative splicing that generates isoforms. Although the literature documenting the presence of PACAP receptors in the central nervous system is vast, their expression during development has not been established yet. Here, we performed quantitative analyses on the expression of PACAP receptors during the postnatal development of the rat retina.
  
  
  METHODS
  Retinas were harvested from postnatal days 0 to 20 (P0-P20). Using a comprehensive primer system, expression changes were followed employing quantitative real-time PCR. Changes at the protein level were detected by immunoblotting using anti-VPAC1, -VPAC2, and -PAC1 receptor antibodies.
  
  
  RESULTS
  The expression of VPAC1 showed increases at P10 and P15. Peaks in VPAC2 expression were observed at P5 and P15. Using splicing variant-specific primers for PAC1 receptor, splicing regulation of Null, Hip, Hop1, and Hiphop1 variants was revealed in correlation with postnatal development. Transcript levels of the Null and Hip variants showed a decline, while Hop1 became the major PACAP receptor by P20. Hiphop1 transcript levels did not display remarkable changes except for a transient increase at P10. Immunoblotting confirmed the presence and expression level changes of the receptors.
  
  
  CONCLUSIONS
  We conclude that both VPAC1 and VPAC2 could have roles at all stages of retinal development, that PACAP acts through a specific set of PAC1 isoforms, and that Hip and Hop1 are predominantly involved in the postnatal development of rat retina.
authors.affiliation: Department of Experimental Zoology and Neurobiology, University of Pécs, Pécs, Hungary.
authors.forename: Mónika
authors.initials: M
authors.lastname: Lakk
authors.forename: Bence
authors.initials: B
authors.lastname: Szabó
authors.forename: Béla
authors.initials: B
authors.lastname: Völgyi
authors.forename: Róbert
authors.initials: R
authors.lastname: Gábriel
authors.forename: Viktória
authors.initials: V
authors.lastname: Dénes
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D015153:Blotting, Western; D018507:Gene Expression Regulation, Developmental; D012326:RNA Splicing; D012333:RNA, Messenger / Q000235:genetics* / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D051236:Receptors, Pituitary Adenylate Cyclase-Activating Polypeptide / Q000096:biosynthesis / Q000235:genetics*; D051239:Receptors, Vasoactive Intestinal Peptide, Type II / Q000096:biosynthesis / Q000235:genetics*; D051238:Receptors, Vasoactive Intestinal Polypeptide, Type I / Q000096:biosynthesis / Q000235:genetics*; D012160:Retina / Q000166:cytology / Q000254:growth & development* / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: D012333:RNA, Messenger; D051236:Receptors, Pituitary Adenylate Cyclase-Activating Polypeptide; D051239:Receptors, Vasoactive Intestinal Peptide, Type II; D051238:Receptors, Vasoactive Intestinal Polypeptide, Type I