Kuroiwa A, Obinata M, Natori S
Eur J Biochem. 1983 Jan 17;130(1):161-5. doi: 10.1111/j.1432-1033.1983.tb07131.x.
Mouse middle-repetitive sequences have been cloned in the bacterial plasmid pBR322. The DNA sequences, expressed only in nuclei, were screened by filter hybridization using nuclear RNA as probes. Several clones were expressed predominantly in the nuclear RNA in certain types of organs. The copy numbers of typical middle-repetitive sequence clones in genomic DNA were analyzed quantitatively and results showed that 10(3)-10(4) copies exist per haploid DNA, indicating that they belong to a relatively abundant class of repeated sequences. Homology within the family of each middle-repetitive sequence ranged from 81% to 94%. The expression of cloned middle-repetitive sequences was analyzed by liquid-phase hybridization with nuclear RNAs from particular organs. The content of transcripts of the middle-repetitive sequence in nuclear RNA of a particular organ was at least 1000 times higher than that in other organs. In steady-state nuclear RNA these transcripts were calculated to amount to 10(2)-10(4) copies per nucleus. Most of these transcripts seem to be retained in the nuclei and do not appear in the cytoplasm.
小鼠中等重复序列已被克隆到细菌质粒pBR322中。仅在细胞核中表达的DNA序列，使用核RNA作为探针通过滤膜杂交进行筛选。几个克隆在某些类型的器官的核RNA中主要表达。对基因组DNA中典型中等重复序列克隆的拷贝数进行了定量分析，结果表明每个单倍体DNA中存在10³ - 10⁴个拷贝，这表明它们属于一类相对丰富的重复序列。每个中等重复序列家族内的同源性范围为81%至94%。通过与来自特定器官的核RNA进行液相杂交，分析了克隆的中等重复序列的表达。特定器官的核RNA中中等重复序列转录本的含量比其他器官中至少高1000倍。在稳态核RNA中，这些转录本经计算每个细胞核中有10² - 10⁴个拷贝。这些转录本中的大多数似乎保留在细胞核中，而不出现在细胞质中。
