DeLotto R, Louis C, Wormington M, Schedl P
Mol Gen Genet. 1982;188(2):299-304. doi: 10.1007/BF00332691.
In this communication, we report the isolation of seven new recombinants derived from the 5S gene locus of Drosophila melanogaster. These recombinants can be divided into three different classes. There are four clones derived from within the 5S gene cluster, two which contain non-5S sequences representing the 5'flanking segment of the gene array and have a structure similar to 12D8 described by Artavanis-Tsakonas et al. (1977), and finally one (22A8) which is shown to contain a DNA segment that is located adjacent to the 3' end of the 5S gene cluster. Analysis of these recombinants supports the model in which all 5S genes of our D. melanogaster Oregon-R wild type strain are arranged in one uninterrupted cluster and are transcribed in the same direction. Interestingly, the 2.5 kb of non-5S RNA coding sequences on the recombinant derived from the 3' edge of the cluster contains at least four genes coding for tRNAs and one of these is located less than 300 bp downstream from the last 5S transcription unit. These tRNA genes are shown to be functional on the basis of the ability of 22A8 DNA to direct the synthesis of tRNA in an in vitro transcription system.
在本通讯中，我们报道了从黑腹果蝇5S基因位点分离出的7个新的重组体。这些重组体可分为三类。有4个克隆源自5S基因簇内部，其中两个包含代表基因阵列5'侧翼片段的非5S序列，其结构类似于Artavanis-Tsakonas等人（1977年）描述的12D8；最后一个（22A8）显示包含一个位于5S基因簇3'端相邻位置的DNA片段。对这些重组体的分析支持了这样一个模型，即我们的黑腹果蝇俄勒冈-R野生型菌株的所有5S基因都排列在一个不间断的簇中，并以相同方向转录。有趣的是，源自簇3'边缘的重组体上2.5 kb的非5S RNA编码序列包含至少四个编码tRNA的基因，其中一个位于最后一个5S转录单元下游不到300 bp处。基于22A8 DNA在体外转录系统中指导tRNA合成的能力，这些tRNA基因被证明是有功能的。
