CIN4, AN INSERT ALTERING THE STRUCTURE OF THE A1 GENE IN ZEA-MAYS, EXHIBITS PROPERTIES OF NONVIRAL RETROTRANSPOSONS
CIN4, AN INSERT ALTERING THE STRUCTURE OF THE A1 GENE IN ZEA-MAYS, EXHIBITS PROPERTIES OF NONVIRAL RETROTRANSPOSONS
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DOI：
10.1002/j.1460-2075.1987.tb02727.x
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发表时间：
1987-12-01
期刊：
影响因子：
11.4
通讯作者：
SAEDLER, H
中科院分区：
文献类型：
--
作者：
SCHWARZSOMMER, Z;LECLERCQ, L;SAEDLER, H
玉米A1基因的野生型等位基因含有一个1.1 kb长的插入片段，称为Cin 4 -1，与其他A1等位基因相比，它改变了转录单位的结构。Cin 4 -1元件是玉米基因组中以50-100个拷贝存在的元件家族的成员。基因组克隆和序列分析的几个家庭成员和他们的侧翼地区允许分类Cin 4作为一个非病毒逆转录转座子。单个Cin 4元件在其3“-末端终止于可变大小（6-11个残基）的寡核苷酸（A）轨道。家族成员的5“-末端相对于最长的Cin 4元件被不均匀地截短。Cin 4元件两侧是小的直接重复，其大小在3和16 bp之间变化。比较的基础上的目标序列和Cin 4的序列，我们建议和讨论的Cin 4整合的机制，通过在RNA模板上的原位cDNA合成的模型。迄今为止分析的最长的Cin 4元件具有两个非重叠的开放阅读框（ORF），包括2793个核苷酸（ORF 1）和3489个核苷酸（ORF 2）。推测的1163个氨基酸长的Cin 4蛋白衍生自ORF 2的序列具有编码逆转录酶样蛋白和DNA结合结构域的能力。这两个结构域的保守模式和Cin 4的整体组织与在动物非病毒逆转录转座子中检测到的相似。讨论了Cin 4的来源和功能。
A wild-type allele of the A1 gene of Zea mays contains a 1.1-kb-long insert termed Cin4-1, which alters the structure of the transcription unit compared to other A1 alleles. The Cin4-1 element is a member of a family of elements occurring in 50-100 copies in the maize genome. Genomic cloning and sequence analysis of several family members and their flanking regions allowed classification of Cin4 as a nonviral retrotransposon. Individual Cin4 elements terminate in an oligo (A) track of variable size (6-11 residues) at their 3''-end. The 5''-ends of family members are heterogeneously truncated with respect to the longest Cin4 element. Cin4 elements are flanked by small direct duplications, the size of which varies between 3 and 16 bp. On the basis of a comparison of the target sequence and the sequence of Cin4 we suggest and discuss a model of the mechanism of Cin4 integration via in situ cDNA synthesis on an RNA template. The longest Cin4 element analysed so far has two non-overlapping open reading frames (ORFs) comprising 2793 nucleotides (ORF1) and 3489 nucleotides (ORF2). The putative 1163 amino acid long Cin4 protein derived from the sequence of ORF2 has the capacity to encode a reverse transcriptase-like protein and a DNA binding domain. The conservation pattern of these two domains and the overall organisation of Cin4 is similar to that detected in nonviral retrotransposons in animals. The origin and function of Cin4 are discussed.