关键词： 昼夜节律   生物节律   生物钟基因   小鼠   小家鼠   生物学研究   定位  

摘要： 时间生物学研究的新突破：小鼠昼夜节律生物钟基因的定位据美国Ｊｏｓｅｐｈ．Ｓ．Ｔａｋａｈａｓｈｉ等在“Ｓｃｉｅｎｃｅ”上报道，他们用Ｎ－乙基－Ｎ－亚硝基脉（ＥＮＵ）处理的小鼠后代筛选昼夜节律生物钟基因突变，鉴定出控制昼夜节律周期及维持节律性生物钟的半显...

关键词： Animals   Base Sequence   Blotting, Northern   Blotting, Northern   Circadian Rhythm   Drosophila melanogaster/genetics   Drosophila melanogaster/physiology   Drosophila Proteins   Drosophila Proteins   Female   Gene Expression   Genotype   Immunohistochemistry   Immunohistochemistry   Locomotion   Male   Molecular Sequence Data   Nervous System Physiological Phenomena   Nuclear Proteins   Period Circadian Proteins   Plasmids   Proteins/genetics   Proteins/physiology   Transcription, Genetic   Transformation, Genetic  

摘要： The per gene of D. melanogaster influences or participates in the generation of biological rhythms. Previous experiments have identified the head as the location from which per exerts its effect on circadian rhythms. To localize further this region and to examine the effects of altered levels and altered spatial expression patterns of the per gene on circadian rhythms of locomotor activity, we have characterized transformed lines containing per gene constructs missing substantial cis-acting regulatory information. The data suggest that wild-type levels of per gene expression are necessary in only a small fraction of the nervous system for near wild-type periods, whereas a larger fraction of per-expressing cells in the brain contributes to the strength of the circadian rhythms.

关键词： Science   Humanities and Social Sciences   multidisciplinary  

摘要： The per locus of Drosophila melanogaster has a fundamental role in the construction or maintenance of a biological clock. Three classes of per mutations have been identified: perl mutants have circadian behavioural rhythms with a 29-h rather than a 24-h period, pers mutants have short-period rhythms of 19 h, and per0 mutants have no detectable circadian rhythms1–4. Each of these mutations has a corresponding influence on the 55-s periodicity of male courtship song5. Long-and short-period circadian rhythm phenotypes can also be obtained by altering the dosage of the wild-type gene4: for example, females carrying only one dose of this X-linked gene have circadian rhythms with periodicities about 1 h longer than those carrying two doses. In a previous report6, cloned DNA was used to localize several chromosomal rearrangement breakpoints that alter per locus function. The rearrangements all affected a 7-kilobase (kb) interval that encodes a 4.5-kb poly(A)+ RNA. We report here that when a 7.1-kb fragment from a per+ fly, including the sequences encoding the 4.5-kb transcript, is introduced into the genome of a per0 (arrhythmic) fly by P element-mediated transformation, circadian rhythmicity of behaviour such as eclosion and locomotor activity is restored. The transforming DNA complements per locus deletions and is transcribed, forming a single 4.5-kb poly(A)+ RNA comparableto that produced by wild-type flies.