Ferric, not ferrous, heme activates RNA-binding protein DGCR8 for primary microRNA processing

I Barr; AT Smith; Y Chen; R Senturia; JN Burstyn; F Guo

Journal article

Ferric, not ferrous, heme activates RNA-binding protein DGCR8 for primary microRNA processing

I Barr, AT Smith, Y Chen, R Senturia, JN Burstyn, F Guo

Proceedings of the National Academy of Sciences of the United States of America | NATL ACAD SCIENCES | Published : 2012

DOI: 10.1073/pnas.1114514109

Abstract

The RNA-binding protein DiGeorge Critical Region 8 (DGCR8) and its partner nuclease Drosha are essential for processing of micro- RNA (miRNA) primary transcripts (pri-miRNAs) in animals. Previous work showed that DGCR8 forms a highly stable and active complex with ferric [Fe(III)] heme using two endogenous cysteines as axial ligands. Here we report that reduction of the heme iron to the ferrous [Fe(II)] state in DGCR8 abolishes the pri-miRNA processing activity. The reduction causes a dramatic increase in the rate of heme dissociation from DGCR8, rendering the complex labile. Electronic absorption, magnetic circular dichroism, and resonance Raman spectroscopies indicate that reduction of the..

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University of Melbourne Researchers

Ian Barr Author

Grants

Awarded by National Heart, Lung, and Blood Institute

Funding Acknowledgements

We thank J. Valentine and K. Barnese for use of the anaerobic chamber, J. Feigon and T.C. Brunold for use of spectrophotometers, S. Weitz for sharing reagents, and M. Phillips in the University of California, Los Angeles-Department of Energy Biochemistry Instrumentation Facility for technical support. This project is supported by National Institutes of Health Grants GM080563 (to F.G.) and HL065217 (to J.N.B.).