The stability of the Chlorella nitrate reductase mRNA is determined by the secondary structure of the 5′-UTR: implications for posttranscriptional regulation of nitrate reductase

• Published in: Planta 2002-01, Vol.214 (3), p.488-491
• Main Authors: Cannons, Andrew C., Cannon, Jennifer
• Format: Article
• Language: English
• Subjects: 5' Untranslated Regions - chemistry; 5' Untranslated Regions - genetics; Biological and medical sciences; Chlorella - enzymology; Chlorella - genetics; Fundamental and applied biological sciences. Psychology; Gene expression regulation; Genes; Messenger RNA; Metabolism; Nitrate Reductase; Nitrate Reductases - genetics; Nitrates; Nitrogen; Nitrogen metabolism; Nucleic Acid Conformation; Nucleotides; Plant physiology and development; RAPID COMMUNICATION; RNA; RNA Processing, Post-Transcriptional; RNA Stability; RNA, Messenger - chemistry; RNA, Messenger - genetics; RNA, Messenger - metabolism; Terminator regions; Untranslated regions
• ISSN: 0032-0935; 1432-2048
• DOI: 10.1007/s00425-001-0679-z

Nitrate reductase (NR; EC 1.6.1.1-3) can be controlled at both transcriptional and posttranscriptional levels. Here we describe stability of NR mRNA as a mechanism of control. The NR gene in Chlorella vulgaris (Warburg strain) transcribes a stable mRNA and an unstable mRNA. In-vitro-synthesized transcripts representing these mRNAs show the same stability characteristics. The unstable mRNA is 30 nucleotides longer at the 5′-UTR compared to the stable mRNA. Using an RNA-folding program the 5′-UTR of the longer unstable RNA showed a more extensive stemloop structure compared to the more linear form of the shorter stable mRNA. Transcripts representing RNAs with intermediate 5′-UTRs folded similarly to the long form and were unstable, or similarly to the short form and were more stable. Thus the secondary structure of the 5′-UTR of NR mRNA is important in the stability of NR transcripts in Chlorella and allows the cell to respond to changes in nitrogen source in an energy-efficient manner.