5′-coding sequence of the nasA gene of Azotobacter vinelandii is required for efficient expression

• Published in: FEMS microbiology letters Vol. 359; no. 2; pp. 201 - 208
• Main Authors: Wang, Baomin, Wang, Yumei, Kennedy, Christina
• Format: Journal Article
• Language: English
• Published: England Blackwell Publishing Ltd 01.10.2014; Oxford University Press
• Subjects: adenine‐rich sequence; Ammonium; ammonium compounds; ammonium nitrogen; Azotobacter vinelandii; Azotobacter vinelandii - enzymology; Azotobacter vinelandii - genetics; Bacterial Proteins - genetics; Base Sequence; Codon; DNA Mutational Analysis; gene expression; Gene Expression Regulation, Bacterial; Genes, Bacterial; Microbiology; Molecular Sequence Data; mRNA folding; nitrate nitrogen; Nitrate Reductase - metabolism; Nitrates; nitrite nitrogen; nitrite reductase; Nitrite Reductases - genetics; Nitrite Reductases - metabolism; nitrites; Nucleic Acid Conformation; operon; Operon - genetics; Pseudomonas; reporter genes; RNA, Bacterial - chemistry; RNA, Bacterial - genetics; RNA, Messenger - chemistry; RNA, Messenger - genetics; translation; translation (genetics); mRNA folding; translation; nitrite reductase; adenine-rich sequence; Pseudomonas
• ISSN: 0378-1097; 1574-6968; 1574-6968
• DOI: 10.1111/1574-6968.12570

Abstract The operon nasACBH in Azotobacter vinelandii encodes nitrate and nitrite reductases that sequentially reduce nitrate to nitrite and to ammonium for nitrogen assimilation into organic molecules. Our previous analyses showed that nasACBH expression is subject to antitermination regulation that occurs upstream of the nasA gene in response to the availability of nitrate and nitrite. In this study, we continued expression analyses of the nasA gene and observed that the nasA 5′-coding sequence plays an important role in gene expression, as demonstrated by the fact that deletions caused over sixfold reduction in the expression of the lacZ reporter gene. Further analysis suggests that the nasA 5′-coding sequence promotes gene expression in a way that is not associated with weakened transcript folding around the translational initiation region or codon usage bias. The findings from this study imply that there exists potential to improve gene expression in A. vinelandii by optimizing 5′-coding sequences. A sequence element at the 5′ end of the nasA gene in Azotobacter vinelandii promotes gene expression. Graphical Abstract Figure. A sequence element at the 5′ end of the nasA gene in Azotobacter vinelandii promotes gene expression.