Yen P H, Davidson N
Cell. 1980 Nov;22(1 Pt 1):137-48. doi: 10.1016/0092-8674(80)90162-2.
The sequence organization and positions of the tRNA genes in a tRNA gene cluster at chromosomal region 42A of the D. melanogaster (Dm) genome have been studied by recombinant DNA methods. A set of overlapping inserts of Dm DNA cloned in a lambdoid vector and extending in both directions from the Drosophila tRNA gene-bearing fragment of plasmid pCIT12 has been isolated by the procedure of "chromosomal walking." The isolated region has a total length of 94 kb of which a central 46 kb region contains eight tRNAAsn genes, four tRNA2Arg genes, five tRNA2Lys genes and one tRNAIle gene. The genes are irregularly spaced and transcribed from both strands; they occur to some extent in subclusters. Thus this sequence organization is totally different from the tandem repeat organizaiton seen in many 5S rRNA gene clusters of higher eucaryotes and in one Xenopus rRNA gene clusters of higher eucaryotes and in one Xenopus tRNA gene cluster.
利用重组DNA方法研究了黑腹果蝇（Dm）基因组染色体区域42A中tRNA基因簇的tRNA基因的序列组织和位置。通过“染色体步移”程序，分离出一组克隆在λ噬菌体载体中的Dm DNA重叠插入片段，这些片段从质粒pCIT12的果蝇tRNA基因携带片段向两个方向延伸。分离出的区域全长94kb，其中央46kb区域包含8个tRNAAsn基因、4个tRNA2Arg基因、5个tRNA2Lys基因和1个tRNAIle基因。这些基因间隔不规则，从两条链转录；它们在一定程度上以亚簇形式出现。因此，这种序列组织与在许多高等真核生物的5S rRNA基因簇以及一个非洲爪蟾rRNA基因簇和一个非洲爪蟾tRNA基因簇中看到的串联重复组织完全不同。
