Retracted: Nuclear localization and in situ DNA damage by Mycobacterium tuberculosis nucleoside-diphosphate kinase

Area of Science:

• Microbiology
• Molecular Biology
• Biochemistry

Background:

• Nucleoside-diphosphate kinase (NdK) is crucial for maintaining cellular nucleoside triphosphate pools.
• The secretion of Mycobacterium tuberculosis NdK (mNdK) suggests a role beyond intracellular metabolism.
• The biological significance of mNdK secretion remains unclear.

Purpose of the Study:

• To investigate the biological role and function of the secreted Mycobacterium tuberculosis nucleoside-diphosphate kinase (mNdK).
• To determine the cellular localization and enzymatic activity of mNdK in host cells.

Main Methods:

• Expression of mNdK fused to green fluorescent protein in HeLa and COS-1 cells.
• Detection of mNdK localization using microscopy.
• Assay of mNdK activity on isolated nuclei and plasmid DNA using surface plasmon resonance and electron paramagnetic resonance.
• Investigation of metal ion and oxygen dependency for DNA cleavage.

Main Results:

• mNdK was detected within the nuclei of transfected HeLa and COS-1 cells.
• mNdK induced in situ damage to chromosomal DNA.
• mNdK binds supercoiled plasmid DNA and cleaves it in a metal ion-dependent manner.
• DNA cleavage is mediated by superoxide radicals and requires molecular oxygen.

Conclusions:

• Secreted mNdK localizes to host cell nuclei and possesses DNA damaging capabilities.
• The DNA-damaging activity of mNdK, potentially involving superoxide radicals, suggests a mechanism for host cell manipulation.
• mNdK may contribute to Mycobacterium tuberculosis pathogenesis by inducing host cell death, facilitating pathogen dissemination.