Transcription factors Rv0081 and Rv3334 connect the early and the enduring hypoxic response of Mycobacterium tuberculosis

ABSTRACT

The ability of Mycobacterium tuberculosis (M. tb) to survive and persist in the host for decades in an asymptomatic state is an important aspect of tuberculosis pathogenesis. Although adaptation to hypoxia is thought to play a prominent role underlying M. tb persistence, how the bacteria achieve this goal is largely unknown. Rv0081, a member of the DosR regulon, is induced at the early stage of hypoxia while Rv3334 is one of the enduring hypoxic response genes. In this study, we uncovered genetic interactions between these two transcription factors. RNA-seq analysis of ΔRv0081 and ΔRv3334 revealed that the gene expression profiles of these two mutants were highly similar. We also found that under hypoxia, Rv0081 positively regulated the expression of Rv3334 while Rv3334 repressed transcription of Rv0081. In addition, we demonstrated that Rv0081 formed dimer and bound to the promoter region of Rv3334. Taken together, these data suggest that Rv0081 and Rv3334 work in the same regulatory pathway and that Rv3334 functions immediately downstream of Rv0081. We also found that Rv3334 is a bona fide regulator of the enduring hypoxic response genes. Our study has uncovered a regulatory pathway that connects the early and the enduring hypoxic response, revealing a transcriptional cascade that coordinates the temporal response of M. tb to hypoxia.

KEYWORDS:

• Rv0081
• Rv3334
• Mycobacterium tuberculosis
• hypoxia
• transcriptional factors

Abbreviations

M. tb	=	Mycobacterium tuberculosis
TB	=	tuberculosis
WHO	=	World Health Organization
LTBI	=	latent TB infection
HER	=	enduring hypoxic response
EMSAs	=	electrophoretic mobility shift assays
ORF	=	open reading frame

Acknowledgments

The authors gratefully acknowledge financial support from China Scholarship Council.

Disclosure statement

No potential conflict of interest was reported by the authors.

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Additional information

Funding

This study was supported by grants from the China’s 13th Five Year Programs for the prevention and cure of great infectious diseases [No. 2017ZX10201301-005, 2018ZX10731301-001-005];National Key R&D Program of China [No.2018YFD0500900];International cooperation and exchange program of Shanghai Municipal [No. 16430724000] and grants from Canadian Institutes of Health Research [MOP-106559, PJT156261]. The authors gratelfully acknowledge financial support from China Scholarship Council.