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AtNAP7 is a plastidic SufC-like ATP-binding cassette/ATPase essential for Arabidopsis embryogenesis

Xiang Ming Xu1, Simon Geir Møller

  • 1Department of Biology, University of Leicester, Leicester LE1 7RH, United Kingdom.

Proceedings of the National Academy of Sciences of the United States of America
|June 9, 2004
PubMed

Insights

Iron-sulfur cluster assembly is crucial for plant development. A specific protein, AtNAP7, is essential for Arabidopsis embryogenesis, highlighting the importance of plastid iron-sulfur cluster maintenance.

Area of Science:

  • Plant Biology
  • Biochemistry
  • Molecular Biology

Background:

  • Iron-sulfur (Fe-S) clusters are vital cofactors in numerous cellular processes across all domains of life.
  • Defects in Fe-S cluster availability cause human diseases, underscoring their importance.
  • While Fe-S proteins are crucial in plants, their biogenesis and the consequences of assembly defects remain largely unknown.

Purpose of the Study:

  • To investigate the role of iron-sulfur cluster biogenesis in plant development, specifically focusing on the SufC homolog AtNAP7 in Arabidopsis thaliana.
  • To elucidate the function and localization of AtNAP7 and its contribution to Fe-S cluster homeostasis during embryogenesis.

Main Methods:

  • Generated Arabidopsis mutants deficient in the AtNAP7 gene.
  • Analyzed embryo lethality and developmental defects.
  • Determined AtNAP7 localization using microscopy.
  • Assessed the ability of AtNAP7 to rescue bacterial mutants under oxidative stress.
  • Investigated protein interactions between AtNAP7 and other SUF system components.

Main Results:

  • Arabidopsis plants lacking AtNAP7 exhibited lethality at the globular stage of embryogenesis.
  • AtNAP7 is expressed in key developmental tissues, including meristems and developing embryos.
  • AtNAP7 is localized to plastids and can functionally complement an E. coli SufC mutant.
  • Mutant embryos displayed abnormal plastid development with disorganized thylakoids.
  • AtNAP7 interacts with AtNAP6 (a SufD homolog), suggesting a functional SUF system within Arabidopsis plastids.

Conclusions:

  • AtNAP7 is a conserved SufC protein essential for iron-sulfur cluster biogenesis and/or repair in plants.
  • Plastidic iron-sulfur cluster maintenance is critical for successful Arabidopsis embryogenesis.
  • The SUF system likely operates within Arabidopsis plastids to ensure Fe-S cluster homeostasis.

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