德國雷根斯堡大學(xué)的Ralf Stanewsky和同事們通過研究果蠅的Veela突變體,，揭開了自然遺傳突變體和晝夜基因座突變之間相互關(guān)系的秘密，該文發(fā)表在11月14日的PNAS雜志上。
持續(xù)照明條件下果蠅突變體表現(xiàn)出的晝夜節(jié)奏性（circadian rhythmicity）特征,，為科學(xué)家們闡明生物體內(nèi)晝夜節(jié)律時間鐘(circadian clock；也可稱生物鐘；biological clock；見備注)和環(huán)境同步化的內(nèi)在機制提供重要線索,。蛋白質(zhì)Cryptochrome, Timeless和Jetlag是至今發(fā)現(xiàn)的調(diào)控該同步化的關(guān)鍵蛋白。通過研究稱作Veela的果蠅突變體（它可以在持續(xù)有關(guān)照的環(huán)境下表現(xiàn)出節(jié)奏性）, Ralf Stanewsky和同事們揭開了自然遺傳突變體和晝夜基因座突變之間相互關(guān)系的秘密1,。圖譜展示了Veela緊挨在Timeless基因的附近,，然而序列分析并沒有發(fā)現(xiàn)任何Timeless的突變。但作者發(fā)現(xiàn)Veela果蠅有著Timeless的ls等位基因,。野生型果蠅可以攜帶ls等位基因或s等位基因,；ls等位基因編碼的Timeless蛋白使得個體對光誘導(dǎo)的降解過程更不敏感。因為ls等位基因本身并不能揭示在Veela突變體身上發(fā)現(xiàn)的表型,，作者隨后分析了Jetlag基因，該基因就在Veela的附近,。研究者們在該基因上發(fā)現(xiàn)了一個編碼突變,。作者懷疑Timeless 的ls等位基因與Jetlag突變的結(jié)合導(dǎo)致了Veela表型。確實地,，當(dāng)Jetlag突變遇到Timeless 的s等位基因時,，果蠅表現(xiàn)出正常的表型。
1 N. Peschel, S. Veleri, and R. Stanewsky, Proc Natl Acad Sci U S A 103 (46), 17313 (2006).
Lab:Institute of Zoology, University of Regensburg, Universitatsstrasse 31, 93040 Regensburg, Germany.
備注：
生物節(jié)律主要有：1) 近日節(jié)律（20-28小時,，即晝夜節(jié)律circadian rhythm）,；2) 近月節(jié)律（30±7天circamensual rhythm）；3) 近年節(jié)律（12±2月circannual rhythm）,。生物節(jié)律具有四個基本特征：1）內(nèi)源性,；2) 遺傳性；3）獨立性,；4) 可調(diào)性,。
部分英文原文：
Veela defines a molecular link between Cryptochrome and Timeless in the light-input pathway to Drosophila's circadian clock
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Fig. 1. Locomotor activity of individual flies during constant light. Genotypes are indicated on top of each actogram accompanied by its corresponding autocorrelogram. Actograms show the raw activity of each fly, in which the height of each bar indicates the amount of locomotion during a 30-min interval. Autocorrelograms show period and rhythmicity index values of each fly as an objective way to determine rhythmicity (see Materials and Methods). The upper four flies also have their polymorphisms in regard to the tim and jet variants indicated (see text). Flies to the left are arrhythmic; individuals to the right are rhythmic. al I-40 and al I-3 each designate recombinants resulting from meiotic crossing over between two second chromosomes in females heterozygous for Veela and the marker combination al dp b pr. Both the I-40 and the I-3 recombinants carry the al marker and the jetc variant but differ with respect to tim. Note that al I-40 flies behaved arrhythmically in LL (like the controls), although they carry jetc.
更多原文鏈接：http://intl.pnas.org/cgi/content/figsonly/103/46/17313
