Hardin Paul E, Krishnan Balaji, Houl Jerry H, Zheng Hao, Ng Fanny S, Dryer Stuart E, Glossop Nick R J
Department of Biology and Biochemistry, University of Houston, Houston, TX 771204-5001, USA.
Novartis Found Symp. 2003;253:140-50; discussion 150-60.
Drosophila circadian oscillators comprise interlocked period (per)/timeless (tim) and Clock (Clk) transcriptional/translational feedback loops. Within these feedback loops, CLOCK (CLK) and CYCLE (CYC) bind E-box elements to activate per and tim transcription, and we now show that at the same time CLK-CYC repress Clk by activating the transcriptional repressor vrille (vri), thus accounting for the opposite cycling phases of these transcripts and identifying vri as the negative component of the Clk-feedback-loop. The core oscillator mechanism is assumed to be the same for oscillators in different tissues. However, we have shown that CRYPTOCHROME (CRY) has a light-independent function in the oscillator that controls olfaction rhythms, suggesting that CRY may function within the oscillator mechanism itself as it does in mammals. These olfaction rhythms require the function of 'peripheral' oscillators which are distinct from the 'central' lateral neuron (LN) oscillators that mediate locomotor activity rhythms. Preliminary results show that antennal oscillator cells are sufficient and LNs are not necessary for olfaction rhythms, indicating that unlike the situation in mammals, the central oscillator has little impact on the olfaction rhythm oscillator under these conditions.
果蝇昼夜节律振荡器由相互关联的周期（per）/无时间性（tim）和生物钟（Clk）转录/翻译反馈环组成。在这些反馈环中，生物钟（CLK）和周期蛋白（CYC）结合E-box元件以激活per和tim转录，并且我们现在表明，同时CLK-CYC通过激活转录抑制因子维里（vri）来抑制Clk，从而解释了这些转录本相反的循环相位，并确定vri为Clk反馈环的负向组成部分。核心振荡器机制被认为在不同组织的振荡器中是相同的。然而，我们已经表明，隐花色素（CRY）在控制嗅觉节律的振荡器中具有与光无关的功能，这表明CRY可能在振荡器机制本身内发挥作用，就像它在哺乳动物中那样。这些嗅觉节律需要“外周”振荡器的功能，这些振荡器与介导运动活动节律的“中央”侧神经元（LN）振荡器不同。初步结果表明，触角振荡器细胞对于嗅觉节律是足够的，而LN对于嗅觉节律不是必需的，这表明与哺乳动物的情况不同，在这些条件下中央振荡器对嗅觉节律振荡器几乎没有影响。
