Temperature-modulated alternative splicing and promoter use in the circadian clock gene frequency
Temperature-modulated alternative splicing and promoter use in the circadian clock gene frequency
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DOI：
10.1091/mbc.e05-08-0756
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发表时间：
2005-12-01
影响因子：
3.3
通讯作者：
Dunlap, JC
中科院分区：
文献类型：
--
作者：
Colot, HV;Loros, JJ;Dunlap, JC
粗糙脉孢菌生物钟的核心成分频率的表达显示了对环境非常敏感的每日周期。长度相差99个氨基酸的两种形式的FRQ，LFRQ和SFRQ，是从替代的起始密码子合成的，并且它们的比率随温度的变化有助于在一定温度范围内的稳健节律性。我们已经发现frq的表达是令人惊讶的复杂，尽管我们早期预测的一个简单的转录单位的基础上有限的cDNA测序。两种不同的环境调节的主要启动子驱动初级转录物，其受环境影响的选择性剪接产生六种不同的主要mRNA种类以及次要形式。温度敏感的选择性剪接决定AUG的选择，并因此决定LFRQ与SFRQ的比率。六个上游ORF中的四个被剪接出绝大多数frq mRNA种类。5 'UTR中的替代剪接位点选择和两个主要启动子的相对使用也受到温度的影响，并且这两个启动子受到光的差异调节。进化比较与Sordariaceae揭示保守的5' UTR序列，以及显着的保守的选择性剪接事件，支持其相关性的时钟功能的适当调节。
The expression of FREQUENCY, a central component of the circadian clock in Neurospora crassa, shows daily cycles that are exquisitely sensitive to the environment. Two forms of FRQ that differ in length by 99 amino acids, LFRQ and SFRQ, are synthesized from alternative initiation codons and the change in their ratio as a function of temperature contributes to robust rhythmicity across a range of temperatures. We have found frq expression to be surprisingly complex, despite our earlier prediction of a simple transcription unit based on limited cDNA sequencing. Two distinct environmentally regulated major promoters drive primary transcripts whose environmentally influenced alternative splicing gives rise to six different major mRNA species as well as minor forms. Temperature-sensitive alternative splicing determines AUG choice and, as a consequence, the ratio of LFRQ to SFRQ. Four of the six upstream ORFs are spliced out of the vast majority of frq mRNA species. Alternative splice site choice in the 5'UTR and relative use of two major promoters are also influenced by temperature, and the two promoters are differentially regulated by light. Evolutionary comparisons with the Sordariaceae reveal conservation of 5' UTR sequences, as well as significant conservation of the alternative splicing events, supporting their relevance to proper regulation of clock function.