非洲爪蟾基因组中组蛋白基因的组织方式。
The organization of the histone genes in the genome of Xenopus laevis.
作者信息
van Dongen W, de Laaf L, Zaal R, Moorman A, Destrée O
出版信息
Nucleic Acids Res. 1981 May 25;9(10):2297-311. doi: 10.1093/nar/9.10.2297.
We have studied the organization of the histone genes in the DNA from several individuals of Xenopus laevis. For that purpose, Southern blots of genomic DNA, that was digested with several restriction enzymes, were hybridized with radioactively labeled DNA fragments from clone X1-hi-1 (14), containing genes for Xenopus histones H2A, H2B, H3 and H4. In the DNA of all animals that were screened we found a major repeating unit of 14 kilobasepairs, which contains genes for histones H2A, H2B, H3 and H4 (H1 not tested) and is represented up to 30 times in the genome. The order of the genes in this major repeating unit is H4 - H3 - H2A - H2B. This order is different from that in the histone DNA of clone X1-hi-1, i.e. H3 - H4 - H2A - H2B. In addition to the genes in the major repeating unit, histone genes are present in unique restriction fragments in numbers that vary from one animal to another. The restriction patterns for the histone genes in these unique fragments were found to be different for all eight Xenopus individuals that were screened. The cloned Xenopus histone gene fragment X1-hi-1 represents such a unique fragment and is not present in the DNA of each single individual. The total number of genes coding for each of the nucleosomal histones is 45-50 per haploid genome.
我们研究了非洲爪蟾几个个体的DNA中组蛋白基因的组织情况。为此，用几种限制性内切酶消化基因组DNA后进行Southern杂交，将其与来自克隆X1-hi-1（14）的放射性标记DNA片段杂交，该克隆含有非洲爪蟾组蛋白H2A、H2B、H3和H4的基因。在所有被检测动物的DNA中，我们发现了一个14千碱基对的主要重复单元，它包含组蛋白H2A、H2B、H3和H4的基因（未检测H1），在基因组中重复出现多达30次。这个主要重复单元中基因的顺序是H4 - H3 - H2A - H2B。这个顺序与克隆X1-hi-1的组蛋白DNA中的顺序不同，即H3 - H4 - H2A - H2B。除了主要重复单元中的基因外，组蛋白基因还存在于独特的限制性片段中，其数量因动物个体而异。在所有被检测的8个非洲爪蟾个体中，这些独特片段中组蛋白基因的限制性图谱各不相同。克隆的非洲爪蟾组蛋白基因片段X1-hi-1就代表这样一个独特片段，并非存在于每个个体的DNA中。每个单倍体基因组中编码各核小体组蛋白的基因总数为45 - 50个。
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