在 KaiC 酸化的昼夜节律中没有转录-翻译反
Jun Tomita1, Masato Nakajima, Takao Kondo
1Division of Biological Science, Graduate School of Science, Nagoya University, and Core Research for Evolutional Science and Technology, Japan Science and Technology Agency, Furo-cho, Chikusa-ku, Nagoya 464-8602, Japan.
概括
蓝藻细菌的昼夜时钟是由KaiC酸化驱动的,其功能独立于新的转录和翻译. 这种强大的节奏表明温度补偿,即使没有信使RNA积累.
科学领域:
- * 循环节生物学
- * 生物钟的分子机制
- * 蓝藻细菌生理学
背景情况:
- *自我调节的转录-翻译反循环被认为是大多数生物体中昼夜节律生成的必要条件.
- * 假设Synechococcus elongatus中的KaiC蛋白是这样一个负反循环的一部分.
- *了解昼夜时钟的核心组成部分对于破译生命中的时间调节至关重要.
研究的目的:
- * 为了研究Synechococcus elongatus中昼夜节律的转录和翻译的必要性.
- * 为了确定KaiC酸化周期在抑制基因表达的条件下是否温度补偿和稳健.
- *阐明蓝藻细菌计时的基本机制.
主要方法:
- * 在持续的黑暗条件下监测KaiC酸化循环.
- *在转录和翻译抑制剂的存在下评估节律持久性.
- *对KaiC自酸化-脱酸化比率进行了体外运动分析.
主要成果:
- * 在没有kaiBC信使RNA积累的情况下,观察到强大的,温度补偿的KaiC酸化昼夜循环.
- *即使转录或翻译被抑制,观察到的节奏仍然存在.
- *体外动力学研究证实了KaiC自酸化-脱酸化的温度补偿.
结论:
- * 蓝藻细菌的昼夜时钟可以保持强大的温度补偿计时,独立于 de novo 转录和翻译.
- *Synechococcus elongatus的循环节律不仅仅依赖于自我调节的转录-翻译反循环.
- *这些发现挑战了转录-翻译反对于昼夜节律生成的普遍要求.
相关概念视频
Biological Clocks and Seasonal Responses
The circadian—or biological—clock is an intrinsic, timekeeping, molecular mechanism that allows plants to coordinate physiological activities over 24-hour cycles called circadian rhythms. Photoperiodism is a collective term for the biological responses of plants to variations in the relative lengths of dark and light periods. The period of light-exposure is called the photoperiod.
Circadian Rhythms and Gene Regulation
The biological clock is involved in many aspects of regulating complex physiology in all animals. It was in 1935 when German zoologists, Hans Kalmus and Erwin Bünning, discovered the existence of circadian rhythm in Drosophila melanogaster. However, the internal molecular mechanisms behind the circadian clock remained a mystery until 1984, when Jeffrey C. Hall, Michael Rosbash, and Michael W. Young discovered the expression of the Per gene oscillating over a 24-hour cycle. In subsequent years,...
Positive Regulator Molecules
Mitotic cell division results in daughter cells that exactly resemble the parent cell. However, errors in the DNA replication or distribution of genetic material may lead to genetic mutations that may be passed down to every new cell formed from the resulting abnormal cell. Propagation of such mutant cells is restricted through checkpoint mechanisms present at different stages of the cell cycle. These checkpoints involve regulator molecules that either promote or demote cell cycle events.
Feedback Regulation of Calcium Concentration
Calcium is an essential signaling molecule required for various cellular functions. Calcium pumps and ion channels on cell and organellar membranes, such as those on the endoplasmic reticulum (ER), regulate calcium concentrations inside the cell. They remain closed, keeping the cytosolic calcium levels low at a resting state.
Various transmembrane receptors, such as G protein-coupled receptors (GPCRs), elicit a response to extracellular signals by increasing cytosolic calcium. Activated GPCRs...
Various transmembrane receptors, such as G protein-coupled receptors (GPCRs), elicit a response to extracellular signals by increasing cytosolic calcium. Activated GPCRs...
Calmodulin-dependent Signaling
Calmodulin (CaM) is a calcium-binding protein in eukaryotes that controls various calcium-regulated cellular processes. It has four calcium-binding sites that bind calcium to form the calcium-calmodulin ( Ca2+-CaM) complex. GPCR stimulation increases the calcium levels in the cells that bind to CaM and induces a conformational change.
The Ca2+-CaM complex does not have enzymatic activity by itself. Instead, the complex binds downstream target proteins, including membrane proteins or enzymes,...
The Ca2+-CaM complex does not have enzymatic activity by itself. Instead, the complex binds downstream target proteins, including membrane proteins or enzymes,...
Circadian Rhythms and Gene Regulation
The biological clock is involved in many aspects of regulating complex physiology in all animals. It was in 1935 when German zoologists, Hans Kalmus and Erwin Bünning, discovered the existence of circadian rhythm in Drosophila melanogaster. However, the internal molecular mechanisms behind the circadian clock remained a mystery until 1984, when Jeffrey C. Hall, Michael Rosbash, and Michael W. Young discovered the expression of the Per gene oscillating over a 24-hour cycle. In subsequent years,...


