INTEGRATION AND NONRANDOM MUTATION OF A PLASMA-MEMBRANE PROTON ATPASE GENE FRAGMENT WITHIN THE BS1 RETROELEMENT OF MAIZE
INTEGRATION AND NONRANDOM MUTATION OF A PLASMA-MEMBRANE PROTON ATPASE GENE FRAGMENT WITHIN THE BS1 RETROELEMENT OF MAIZE
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DOI：
10.1105/tpc.6.8.1177
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发表时间：
1994-08-01
期刊：
影响因子：
11.6
通讯作者：
BENNETZEN, JL
中科院分区：
文献类型：
--
作者：
JIN, YK;BENNETZEN, JL
逆转录转座子是真核生物中的一类可移动 DNA 序列，通过逆转录 RNA 中间体进行转座。含有长末端重复序列的逆转录转座子具有动物逆转录病毒的许多属性，但之前并未观察到它们能像 RNA 肿瘤病毒获取癌基因那样获得部分细胞基因。我们在玉米 Bs1 逆转录转座子中发现了与质膜质子 ATP 酶基因的同源性，这种同源性使我们克隆了玉米质膜质子 ATP 酶基因，我们将其命名为 Mha1。 Mha1 的序列证实该 ATPase 基因的 654 bp 存在于 Bs1 中；该片段代表外显子 4 的最后一个氨基酸、所有外显子 5 至 9 以及外显子 10 的一部分。所有内含子均已从该获得的 DNA 中去除，而 81 个单碱基桶。 Bs1 中的 183 bp 替换和删除区分了这些连续片段。二次突变导致衍生的 Bs1 蛋白序列的变化少于中性事件的预测，这表明获得的 Mha1 DNA 在 Bs1 内执行选定的功能。这些数据表明逆转录转座子可以在其遗传物质内整合并传输标准核基因转录物的一部分。或者，这些结果表明 Bs1 可能代表植物逆转录病毒的缺陷版本。
Retrotransposons are a class of mobile DNA sequences in eukaryotes that transpose through a reverse-transcribed RNA intermediate. Retrotransposons containing long terminal repeats have many of the attributes of retroviruses in animals but have not been previously observed to acquire a portion of a cellular gene as RNA tumor viruses do with oncogenes. We have found homology to plasma membrane proton ATPase genes within the Bs1 retrotransposon of maize, and this homology led us to clone the maize plasma membrane proton ATPase gene, which we have named Mha1. The sequence of Mha1 confirmed that 654 bp of this ATPase gene are present in Bs1; this segment represents the last amino acid of exon 4, all of exons 5 to 9, and part of exon 10. All introns have been removed from this acquired DNA, whereas 81 single base pail. substitutions and a deletion of 183 bp in Bs1 differentiate these contiguous segments. The secondary mutations led to fewer changes in the derived Bs1 protein sequence than predicted for neutral events, suggesting that the acquired Mha1 DNA performs a selected function within Bs1. These data indicate that a retrotransposon can incorporate and transmit a portion of a standard nuclear gene transcript within its genetic material. Alternatively, these results suggest that Bs1 may represent a defective version of a plant retrovirus.