Profile of rhythmic gene expression in the livers of obese diabetic KK-A(y) mice.
Although a number of genes expressed in most tissues, including the liver, exhibit circadian regulation, gene expression profiles are usually examined only at one scheduled time each day. In this study, we investigated the effects of obese diabetes on the hepatic mRNA levels of various genes at 6-h intervals over a single 24-h period. Microarray analysis revealed that many genes are expressed rhythmically, not only in control KK mice but also in obese diabetic KK-A(y) mice. Real-time quantitative PCR verified that 19 of 23 putative circadianly expressed genes showed significant 24-h rhythmicity in both strains. However, obese diabetes attenuated these expression rhythms in 10 of 19 genes. More importantly, the effects of obese diabetes were observed throughout the day in only two genes. These results suggest that observation time influences the results of gene expression analyses of genes expressed circadianly.
Ando
Hitoshi
H
Division of Clinical Pharmacology, Department of Pharmacology, School of Medicine, Jichi Medical University, 3311-1 Yakushiji, Shimotsuke, Tochigi 329-0498, Japan.
Oshima
Yasuo
Y
Yanagihara
Hayato
H
Hayashi
Yohei
Y
Takamura
Toshinari
T
Kaneko
Shuichi
S
Fujimura
Akio
A
D000818:Animals; D056926:CLOCK Proteins; D002940:Circadian Rhythm / Q000502:physiology*; D003924:Diabetes Mellitus, Type 2 / Q000378:metabolism*; D005260:Female; D015870:Gene Expression; D020869:Gene Expression Profiling; D051379:Mice; D008820:Mice, Obese; D009765:Obesity / Q000378:metabolism*; D015534:Trans-Activators / Q000235:genetics / Q000378:metabolism*
D015534:Trans-Activators; D056926:CLOCK Proteins; C538944:Clock protein, mouse