Lezzhov Alexander A, Atabekova Anastasia K, Chergintsev Denis A, Solovyev Andrey G, Morozov Sergey Y
A. N. Belozersky Institute of Physico-Chemical Biology, Moscow State University, 119992 Moscow, Russia.
Plants (Basel). 2025 Apr 14;14(8):1205. doi: 10.3390/plants14081205.
Retrozymes are a class of non-autonomous plant retrotransposons that have long terminal repeats (LTRs) containing hammerhead ribozymes (HHRs) that facilitate the circularization of the retrozyme RNA. The LTR of retrozyme 1 (NbRZ1) has been shown to contain a promoter that directs transcription of this retroelement. In this study, we identified the transcription start site of the promoter contained in the LTR of NbRZ1 and mapped the promoter region essential for its transcriptional activity. Using transgenic plants carrying the GUS gene under the control of the NbRZ1 LTR, the NbRZ1 transcript was demonstrated to potentially encode a protein targeted for proteasomal degradation in the plant cell. Overexpression of this protein in plants using a viral expression vector was found to cause severe necrosis. The data presented suggest a tight regulation of the expression of the NbRZ1-encoded polypeptide in plants and its potential functional importance, although further research is needed to determine whether circular and/or linear retrozyme RNA forms can be translated in plants.
逆转录酶是一类非自主植物逆转录转座子，其具有长末端重复序列（LTRs），这些长末端重复序列包含锤头状核酶（HHRs），可促进逆转录酶RNA的环化。逆转录酶1（NbRZ1）的LTR已被证明含有一个启动子，该启动子指导这种逆转录元件的转录。在本研究中，我们确定了NbRZ1的LTR中所含启动子的转录起始位点，并绘制了其转录活性所必需的启动子区域。使用在NbRZ1 LTR控制下携带GUS基因的转基因植物，证明NbRZ1转录本可能编码一种在植物细胞中靶向蛋白酶体降解的蛋白质。使用病毒表达载体在植物中过表达这种蛋白质会导致严重坏死。所呈现的数据表明植物中NbRZ1编码的多肽表达受到严格调控及其潜在的功能重要性，尽管还需要进一步研究来确定环状和/或线性逆转录酶RNA形式是否能在植物中翻译。
