title: No circadian rhythms in testis: Period1 expression is clock independent and developmentally regulated in the mouse.
abstract: Spermatogenesis is a process whereby haploid spermatozoa differentiate through meiosis from precursor stem cells. We examined the expression of circadian clock genes in the testis, to assess clock control over the timing of different developmental events. Clock genes are known to oscillate with circadian rhythmicity in the central clock structure, the suprachiasmatic nucleus of the hypothalamus, but also in peripheral tissues. Here we show that Per1 gene expression in the testis is constant over a 24-h period and that the Per1 transcript is expressed at a level higher than the peak values of the Per1 oscillations observed for other tissues. Bmal1, another clock gene whose expression oscillates in other tissues, also shows constant expression levels in the testis. In addition, the levels and phosphorylation state of the PER1 protein are not oscillating at all times of day. Strikingly, Per1 is restricted primarily to step 7 to 10 spermatids and thus appears to be developmentally regulated. The expression of the Clock transcript is also developmentally regulated, but it is found principally in spermatogonia and spermatocytes up until the time of the first meiotic division. Per1 expression is not altered in testes from Clock mutant mice, suggesting that CLOCK does not activate Per1 in male germ cells, in contrast to what it does in other mouse tissues. Taken together, our observations suggest that the testis, in contrast to all other peripheral tissues, lacks a functioning circadian clock.
authors.affiliation: Institut de Génétique et de Biologie Moléculaire et Cellulaire, Centre National de la Recherche Scientifique-Institut National de la Santé et de la Recherche Médicale-Université Louis Pasteur, BP 10142, 67404 Illkirch-Strasbourg, France.
authors.forename: David
authors.initials: D
authors.lastname: Morse
authors.forename: Nicolas
authors.initials: N
authors.lastname: Cermakian
authors.forename: Stefano
authors.initials: S
authors.lastname: Brancorsini
authors.forename: Martti
authors.initials: M
authors.lastname: Parvinen
authors.forename: Paolo
authors.initials: P
authors.lastname: Sassone-Corsi
mesh_terms: D056930:ARNTL Transcription Factors; D000818:Animals; D051792:Basic Helix-Loop-Helix Proteins; D056926:CLOCK Proteins; D018797:Cell Cycle Proteins; D002940:Circadian Rhythm / Q000235:genetics / Q000502:physiology*; D018507:Gene Expression Regulation, Developmental; D060588:LIM Domain Proteins; D008297:Male; D051379:Mice; D018345:Mice, Knockout; D008817:Mice, Mutant Strains; D009687:Nuclear Proteins / Q000235:genetics* / Q000378:metabolism; D056950:Period Circadian Proteins; D012313:RNA / Q000378:metabolism; D013090:Spermatocytes / Q000378:metabolism; D013091:Spermatogenesis / Q000235:genetics*; D013093:Spermatogonia / Q000378:metabolism; D013737:Testis / Q000378:metabolism*; D015534:Trans-Activators / Q000235:genetics* / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism
chemical_list: D056930:ARNTL Transcription Factors; D051792:Basic Helix-Loop-Helix Proteins; D056926:CLOCK Proteins; D018797:Cell Cycle Proteins; D060588:LIM Domain Proteins; D009687:Nuclear Proteins; D056950:Period Circadian Proteins; D012313:RNA; D015534:Trans-Activators; D014157:Transcription Factors; C538961:Bmal1 protein, mouse; C504657:Fhl5 protein, mouse; C539023:Per1 protein, mouse; C117930:activator of CREM in testis (ACT); C538944:Clock protein, mouse