Jambhekar Ashwini, Amon Angelika
David H. Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
Curr Biol. 2008 Jul 8;18(13):969-75. doi: 10.1016/j.cub.2008.05.047.
A cell's decision to undergo meiosis is regulated by multiple signals. In budding yeast, these signals include mating-type status, nutrient starvation, and respiration; the need for respiration is often manifested as a requirement for a nonfermentable carbon source. We have dissected the roles of respiration and carbon source in promoting entry into the meiotic program. This analysis revealed that respiration is needed throughout meiosis but a nonfermentable carbon source is necessary only prior to the meiotic nuclear divisions. A nonfermentable carbon source serves several roles during the early stages of meiosis. It is required for PolII transcription, DNA replication, and recombination. Finally, although the global downregulation of transcription and lack of DNA replication in nonrespiring cells could be due to a lack of energy, we show that the inability to induce genes initiating entry into the meiotic program is not. We propose that a separate respiration-sensing pathway governs meiotic entry.
细胞进行减数分裂的决定受多种信号调控。在芽殖酵母中，这些信号包括交配型状态、营养饥饿和呼吸作用；对呼吸作用的需求通常表现为对不可发酵碳源的需求。我们剖析了呼吸作用和碳源在促进进入减数分裂程序中的作用。该分析表明，减数分裂全过程都需要呼吸作用，但仅在减数分裂核分裂之前需要不可发酵碳源。不可发酵碳源在减数分裂早期发挥多种作用。它是PolII转录、DNA复制和重组所必需的。最后，尽管在不进行呼吸作用的细胞中转录的整体下调和DNA复制的缺乏可能是由于能量不足，但我们表明无法诱导启动进入减数分裂程序的基因并非如此。我们提出，一条独立的呼吸感应途径控制减数分裂的起始。
