Analysis of the prokineticin 2 system in a diurnal rodent, the unstriped Nile grass rat (Arvicanthis niloticus)
Student Authors
Kazuhiko K. MachidaAcademic Program
NeuroscienceUMass Chan Affiliations
Graduate School of Biomedical Sciences, Neuroscience ProgramWeaver Lab
Neurobiology
Document Type
Journal ArticlePublication Date
2005-04-27Keywords
Amino Acid Sequence; Animals; Brain Chemistry; Circadian Rhythm; DNA, Complementary; Gene Expression Regulation; In Situ Hybridization; Light; Male; Molecular Sequence Data; Polymorphism, Genetic; Rats; Rodentia; Transcription, Genetic; Vascular Endothelial Growth Factor,; Endocrine-Gland-DerivedNeuroscience and Neurobiology
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Show full item recordAbstract
Prokineticin 2 (PK2) is a putative output molecule from the SCN. PK2 RNA levels are rhythmic in the mouse SCN, with high levels during the day, and PK2 administration suppresses nocturnal locomotor activity in rats. The authors examined the PK2 system in a diurnal rodent, Arvicanthis niloticus, to determine whether PK2 or PK2 receptors differ between diurnal and nocturnal species. The major transcript variant of A. niloticus PK2 (AnPK2) encodes a 26-residue signal peptide followed by the presumed mature peptide of 81 residues. Within the grass rat signal sequence, polymorphic sequences and amino acid substitutions were observed relative to mouse and laboratory rats, but the hydrophobic core and cleavage site of the signal sequence were preserved. The mature PK2 peptide is identical among A. niloticus, rat, and mouse. AnPK2 mRNA is rhythmically expressed in the SCN, with peak RNA levels occurring in the morning, preceding peaks of Per1 and Per2 as in mouse SCN. Analysis of prokineticin receptor 2 (PKR2) sequences revealed polymorphisms among the grass rats studied. PKR2 mRNA was expressed in the SCN and paraventricular nuclei of the thalamus and hypothalamus. While further analysis is necessary, there is no clear evidence indicating that a difference in the PK2 ligand/receptor system accounts for diurnality in this rodent species. These data contribute to a growing body of evidence suggesting that the key to diurnality lies downstream of the SCN in A. niloticus.Source
J Biol Rhythms. 2005 Jun;20(3):206-18. Link to article on publisher's siteDOI
10.1177/0748730405275135Permanent Link to this Item
http://hdl.handle.net/20.500.14038/33193PubMed ID
15851527Related Resources
Link to Article in PubMedae974a485f413a2113503eed53cd6c53
10.1177/0748730405275135