Mutational Analysis Supports Three-Hairpin Model of Attenuator for Transcription Regulation of <i>ilvBN</i>C Operon in <i>Corynebacterium glutamicum</i>

The <i>ilvBNC</i> operon in <i>Corynebacterium glutamicum</i> encodes key enzymes for the biosynthesis of branched-chain amino acids (L-isoleucine, L-leucine, and L-valine). This operon has been studied for quite a long time, and it is assumed that three hairpin mRNA structur...

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Main Authors: Ludmila E. Ryabchenko, Igor I. Titov, Tatyana E. Leonova, Tatyana I. Kalinina, Tatyana V. Gerasimova, Marina E. Sheremetieva, Nikolay A. Kolchanov, Tamara M. Khlebodarova, Alexander S. Yanenko
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Language:English
Published: MDPI AG 2025-01-01
Series:Microorganisms
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Online Access:https://www.mdpi.com/2076-2607/13/2/291
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author Ludmila E. Ryabchenko
Igor I. Titov
Tatyana E. Leonova
Tatyana I. Kalinina
Tatyana V. Gerasimova
Marina E. Sheremetieva
Nikolay A. Kolchanov
Tamara M. Khlebodarova
Alexander S. Yanenko
author_facet Ludmila E. Ryabchenko
Igor I. Titov
Tatyana E. Leonova
Tatyana I. Kalinina
Tatyana V. Gerasimova
Marina E. Sheremetieva
Nikolay A. Kolchanov
Tamara M. Khlebodarova
Alexander S. Yanenko
author_sort Ludmila E. Ryabchenko
collection DOAJ
description The <i>ilvBNC</i> operon in <i>Corynebacterium glutamicum</i> encodes key enzymes for the biosynthesis of branched-chain amino acids (L-isoleucine, L-leucine, and L-valine). This operon has been studied for quite a long time, and it is assumed that three hairpin mRNA structures can be formed in its regulatory region; however, their functionality and role in the attenuation mechanism of the <i>ilvBNC</i> operon are not completely clear. In the present work, we performed a mutational analysis of mRNA secondary structures in the regulatory region of the <i>C. glutamicum ilvBNC</i> operon, which allowed us to propose a model of the regulation of its transcription involving three mRNA hairpins that essentially act as a transcription terminator, an antiterminator, and an antiantiterminator. In this work, we proved the existence of a transcription terminator in this operon and experimentally confirmed the effectiveness of its influence on the expression of the <i>ilvBNC</i> operon, AHAS enzyme activity, and valine production. We demonstrated the unique functional features of this attenuator, which, due to the overlapping of the terminator and antiterminator hairpins, is capable of rapid low-energy transitions between them without the complete disruption of the hairpin structures.
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spelling doaj-art-e5b5b19b658940e8adbaa2d1a1cc4c462025-08-20T02:45:00ZengMDPI AGMicroorganisms2076-26072025-01-0113229110.3390/microorganisms13020291Mutational Analysis Supports Three-Hairpin Model of Attenuator for Transcription Regulation of <i>ilvBN</i>C Operon in <i>Corynebacterium glutamicum</i>Ludmila E. Ryabchenko0Igor I. Titov1Tatyana E. Leonova2Tatyana I. Kalinina3Tatyana V. Gerasimova4Marina E. Sheremetieva5Nikolay A. Kolchanov6Tamara M. Khlebodarova7Alexander S. Yanenko8National Research Center “Kurchatov Institute”, Kurchatov Genomic Center, Akademika Kurchatova pl. 1, 123182 Moscow, RussiaDepartment of Systems Biology, Institute of Cytology and Genetics SB RAS, Akademika Lavrentyev Ave., 10, 630090 Novosibirsk, RussiaNational Research Center “Kurchatov Institute”, Kurchatov Genomic Center, Akademika Kurchatova pl. 1, 123182 Moscow, RussiaNational Research Center “Kurchatov Institute”, Kurchatov Genomic Center, Akademika Kurchatova pl. 1, 123182 Moscow, RussiaNational Research Center “Kurchatov Institute”, Kurchatov Genomic Center, Akademika Kurchatova pl. 1, 123182 Moscow, RussiaNational Research Center “Kurchatov Institute”, Kurchatov Genomic Center, Akademika Kurchatova pl. 1, 123182 Moscow, RussiaDepartment of Systems Biology, Institute of Cytology and Genetics SB RAS, Akademika Lavrentyev Ave., 10, 630090 Novosibirsk, RussiaDepartment of Systems Biology, Institute of Cytology and Genetics SB RAS, Akademika Lavrentyev Ave., 10, 630090 Novosibirsk, RussiaNational Research Center “Kurchatov Institute”, Kurchatov Genomic Center, Akademika Kurchatova pl. 1, 123182 Moscow, RussiaThe <i>ilvBNC</i> operon in <i>Corynebacterium glutamicum</i> encodes key enzymes for the biosynthesis of branched-chain amino acids (L-isoleucine, L-leucine, and L-valine). This operon has been studied for quite a long time, and it is assumed that three hairpin mRNA structures can be formed in its regulatory region; however, their functionality and role in the attenuation mechanism of the <i>ilvBNC</i> operon are not completely clear. In the present work, we performed a mutational analysis of mRNA secondary structures in the regulatory region of the <i>C. glutamicum ilvBNC</i> operon, which allowed us to propose a model of the regulation of its transcription involving three mRNA hairpins that essentially act as a transcription terminator, an antiterminator, and an antiantiterminator. In this work, we proved the existence of a transcription terminator in this operon and experimentally confirmed the effectiveness of its influence on the expression of the <i>ilvBNC</i> operon, AHAS enzyme activity, and valine production. We demonstrated the unique functional features of this attenuator, which, due to the overlapping of the terminator and antiterminator hairpins, is capable of rapid low-energy transitions between them without the complete disruption of the hairpin structures.https://www.mdpi.com/2076-2607/13/2/291<i>Corynebacterium glutamicum</i>transcription regulationattenuation<i>ilvBNC</i> operonacetohydroxy acid synthase (AHAS)
spellingShingle Ludmila E. Ryabchenko
Igor I. Titov
Tatyana E. Leonova
Tatyana I. Kalinina
Tatyana V. Gerasimova
Marina E. Sheremetieva
Nikolay A. Kolchanov
Tamara M. Khlebodarova
Alexander S. Yanenko
Mutational Analysis Supports Three-Hairpin Model of Attenuator for Transcription Regulation of <i>ilvBN</i>C Operon in <i>Corynebacterium glutamicum</i>
Microorganisms
<i>Corynebacterium glutamicum</i>
transcription regulation
attenuation
<i>ilvBNC</i> operon
acetohydroxy acid synthase (AHAS)
title Mutational Analysis Supports Three-Hairpin Model of Attenuator for Transcription Regulation of <i>ilvBN</i>C Operon in <i>Corynebacterium glutamicum</i>
title_full Mutational Analysis Supports Three-Hairpin Model of Attenuator for Transcription Regulation of <i>ilvBN</i>C Operon in <i>Corynebacterium glutamicum</i>
title_fullStr Mutational Analysis Supports Three-Hairpin Model of Attenuator for Transcription Regulation of <i>ilvBN</i>C Operon in <i>Corynebacterium glutamicum</i>
title_full_unstemmed Mutational Analysis Supports Three-Hairpin Model of Attenuator for Transcription Regulation of <i>ilvBN</i>C Operon in <i>Corynebacterium glutamicum</i>
title_short Mutational Analysis Supports Three-Hairpin Model of Attenuator for Transcription Regulation of <i>ilvBN</i>C Operon in <i>Corynebacterium glutamicum</i>
title_sort mutational analysis supports three hairpin model of attenuator for transcription regulation of i ilvbn i c operon in i corynebacterium glutamicum i
topic <i>Corynebacterium glutamicum</i>
transcription regulation
attenuation
<i>ilvBNC</i> operon
acetohydroxy acid synthase (AHAS)
url https://www.mdpi.com/2076-2607/13/2/291
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