Barsacchi-Pilone G, Batistoni R, Andronico F, Vitelli L, Nardi I
Chromosoma. 1986;93(5):435-46. doi: 10.1007/BF00285826.
We have studied the structure, genome organization, chromosomal location, conservation across species and transcription on lampbrush chromosomes, of an AT-rich satellite DNA component of the newt, Triturus vulgaris meridionalis. The satellite (Sat G), originally isolated by gradient centrifugation, represents about 2% of the vulgaris genome and comprises a highly repetitive sequence family (HindIII family), whose monomers have been cloned. The repeat units are about 330 bp long, as measured on gels, and a cloned unit (pTvm1) is 310 bp long, as shown by sequencing. Abundant clusters of the HindIII family sequences are located within the pericentric heterochromatin (i.e. the C-bands placed at both sides of, and at a certain distance from, the centromeres) in most chromosomes. Both the sequence family and its overall pattern of chromosomal distribution are conserved within the genus Triturus, despite a few species-specific differences. The great majority of the HindIII family sequences are unexpressed on lampbrush chromosomes; they reside within pericentric, condensed segments of the chromosome axis ("loopless bars"). Only a few sequences are transcribed on some loops, suggesting that transcription promotion does not depend on the satellite sequences themselves.
我们研究了普通蝾螈南方亚种（Triturus vulgaris meridionalis）富含AT的卫星DNA成分的结构、基因组组织、染色体定位、物种间保守性以及在灯刷染色体上的转录情况。最初通过梯度离心分离得到的卫星序列（Sat G）约占普通蝾螈基因组的2%，由一个高度重复序列家族（HindIII家族）组成，其单体已被克隆。经凝胶测量，重复单元长度约为330 bp，测序结果显示克隆单元（pTvm1）长度为310 bp。在大多数染色体中，HindIII家族序列的丰富簇位于着丝粒周围的异染色质内（即位于着丝粒两侧且与着丝粒有一定距离的C带）。尽管存在一些物种特异性差异，但序列家族及其染色体分布的整体模式在蝾螈属内是保守的。HindIII家族的绝大多数序列在灯刷染色体上不表达；它们位于染色体轴的着丝粒周围浓缩区段（“无环棒”）内。只有少数序列在一些环上转录，这表明转录促进并不取决于卫星序列本身。
