The BARE-1 retrotransposon is transcribed in barley from an LTR promoter active in transient assays

被引:102
作者
Suoniemi, A [1 ]
Narvanto, A [1 ]
Schulman, AH [1 ]
机构
[1] UNIV HELSINKI,INST BIOTECHNOL,BIOCTR 1A1A,FIN-00014 HELSINKI,FINLAND
关键词
barley; gene expression; Hordeum vulgare; promoter; retrotransposon; transcription;
D O I
10.1007/BF00021791
中图分类号
Q5 [生物化学]; Q7 [分子生物学];
学科分类号
071010 ; 081704 ;
摘要
The BARE-1 retrotransposon occurs in more than 10(4) copies in the barley genome. The element is bounded by long terminal repeats (LTRs, 1829 bp) containing motifs typical of retrotransposon promoters. These, the presence of predicted priming sites for reverse transcription, and the high conservation for all key functional domains of the coding region suggest that copies within the genome could be active retrotransposons. In view of this, we looked for transcription of BARE-1 within barley tissues and examined the promoter function of the BARE-1 LTR. We demonstrate here that BARE-1-like elements are transcribed in barley tissues, and that the transcripts begin within the BARE-1 LTR downstream of TATA boxes. The LTR can drive expression of reporter genes in transiently transformed barley protoplasts. This is dependent on the presence of a TATA box functional in planta as well. Furthermore, we identify regions within the LTR responsible for expression within protoplasts by deletion analyses of LTR-luc constructs. Similarities between promoter regulatory motifs and regions of the LTR were identified by comparisons to sequence libraries. The activity of the LTR as a promoter, combined with the abundance of BARE-1 in the genome, suggests that BARE-1 may retain the potential for propagation in the barley genome.
引用
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页码:295 / 306
页数:12
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