Molecular analysis of clock gene expression in the avian brain

Gisela Helfer, Andrew E Fidler, Daniela Vallone, Nicholas S Foulkes, Roland Brandstaetter

Research output: Contribution to journalArticle

42 Citations (Scopus)

Abstract

Birds are equipped with a complex circadian pacemaking system that regulates the rhythmicity of physiology and behavior. As with all organisms, transcriptional and translational feedback loops of clock genes represent the basic molecular mechanism of rhythm generation in birds. To investigate avian clock gene expression, partial cDNA sequences of six mammalian clock gene homologs (Bmal1, Clock, Per2, Per3, Cry1, and Cry2) and a novel avian cryptochrome gene (Cry4) were cloned from the house sparrow, a model system in circadian research. Expression patterns were analyzed by semi-quantitative RT-PCR and RNase protection assays using total RNA extracted from adult male house sparrow brains. With the exception of Cry4, pronounced rhythmic mRNA expression of all the clock genes analyzed was encountered, with mRNA levels varying considerably between the various genes. Although some basic features of the molecular circadian feedback loop appear to be similar between mammals and birds, the precise phase relationships of the clock gene mRNA rhythms relative to each other and to the light zeitgeber differ significantly between the house sparrow and mammals. Our results point to the existence of differences in the organization of avian and mammalian circadian clock mechanisms.
Original languageEnglish
Pages (from-to)113-127
Number of pages15
JournalChronobiology International
Volume23
Issue number1-2
DOIs
Publication statusPublished - 2006

Keywords

  • ARNTL transcription factors
  • animals
  • basic helix-loop-helix transcription factors
  • brain
  • CLOCK proteins
  • cryptochromes
  • complementary DNA
  • flavoproteins
  • gene expression regulation
  • male
  • nuclear proteins
  • messenger RNA
  • reverse transcriptase polymerase chain reaction
  • ribonucleases
  • sparrows
  • trans-activators
  • transcription factors

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  • Cite this

    Helfer, G., Fidler, A. E., Vallone, D., Foulkes, N. S., & Brandstaetter, R. (2006). Molecular analysis of clock gene expression in the avian brain. Chronobiology International, 23(1-2), 113-127. https://doi.org/10.1080/07420520500521871