Brown D D, Carrol D, Brown R D
Cell. 1977 Dec;12(4):1045-56. doi: 10.1016/0092-8674(77)90168-4.
A second and minor DNA component containing 5s RNA genes has been purified from the genomic DNA of Xenopus laevis (XIt 5S DNA). Some of its physical and chemical characteristics are described. It contains a 5S RNA gene sequence which has some oocyte and some somatic-specific residues, as well as nucleotides which differ from both types of 5S RNA. There are about 2000 of these 5S RNA genes per haploid complement of DNA compared to about 24,000 of the principal oocyte 5S RNA genes. The multiple repeating units of XIt 5S DNA are homogeneous in length (about 350 base pairs). We present evidence that XIt 5S RNA is transcribed in ovaries but not in somatic cells; XIt 5S DNA may therefore be under the same control as the major oocyte 5S DNA.
已从非洲爪蟾的基因组DNA中纯化出了第二种也是含量较少的含5S RNA基因的DNA组分（XIt 5S DNA）。文中描述了它的一些物理和化学特性。它含有一个5S RNA基因序列，该序列既有一些卵母细胞特异性残基，也有一些体细胞特异性残基，还有与这两种5S RNA都不同的核苷酸。与大约24,000个主要的卵母细胞5S RNA基因相比，每个单倍体DNA互补体中大约有2000个这种5S RNA基因。XIt 5S DNA的多个重复单元长度均一（约350个碱基对）。我们提供的证据表明，XIt 5S RNA在卵巢中被转录，但在体细胞中不被转录；因此，XIt 5S DNA可能与主要的卵母细胞5S DNA受相同的调控。
