Huijser P, Beckers L, Top B, Hermans M, Sinke R, Hennig W
Department of Molecular and Developmental Genetics, University of Nijmegen, Faculty of Sciences, The Netherlands.
Chromosoma. 1990 Dec;100(1):48-55. doi: 10.1007/BF00337602.
Microdissection of the lampbrush loops "threads" and "pseudonucleolus" of Y chromosomes from primary spermatocytes of Drosophila hydei and subsequent microcloning of the DNA yielded several recombinant DNA clones which cross-hybridized in screening the different clone banks. By DNA sequencing we found that the inserts of these cross-hybridizing clones contain blocks of poly[d(C-A].poly[d(G-T)]. Testis RNA contains a large fraction of transcripts with this simple repeated nucleotide sequence. With the aid of transcript in situ hybridization we discovered that the "cones" and "pseudonucleolus" lampbrush loops are the primary sites of transcription of poly[d(C-A)].poly[d(G-T)] in spermatocytes. In addition, we found a strand-specific transcription of (CA/GT)n. In both the "cones" and "pseudonucleolus" the (CA)n strand is transcribed, while in the "pseudonucleolus" (GT)n is also transcribed. Labelled (CA)n probes also react with the protein bodies in spermatid nuclei. These observations are discussed in the context of possible functions of (CA/GT)n transcripts in spermatogenesis.
对海德果蝇初级精母细胞中Y染色体的灯刷环“细丝”和“假核仁”进行显微切割，随后对DNA进行微克隆，得到了几个重组DNA克隆，这些克隆在筛选不同克隆库时发生交叉杂交。通过DNA测序我们发现，这些交叉杂交克隆的插入片段含有聚[d（C-A）]·聚[d（G-T）]片段。睾丸RNA中很大一部分转录本具有这种简单的重复核苷酸序列。借助转录原位杂交，我们发现“锥体”和“假核仁”灯刷环是精母细胞中聚[d（C-A）]·聚[d（G-T）]转录的主要位点。此外，我们发现了（CA/GT）n的链特异性转录。在“锥体”和“假核仁”中，（CA）n链都被转录，而在“假核仁”中（GT）n也被转录。标记的（CA）n探针也与精子细胞核中的蛋白体发生反应。本文结合（CA/GT）n转录本在精子发生中的可能功能对这些观察结果进行了讨论。
