Duke University Medical Center
Faculty and Research

Heitman Lab Members

Silvia Calo Varela
Post-Doctoral Fellow

317 CARL Building
Box 3546 DUMC
Durham, N.C. 27710

Phone: 919.684.2809
Fax: 919.684.5458
Email: silvia.calovarela@duke.edu
Silvia Calo

My name is Silvia, and I am a post-doctoral fellow in Dr. Heitman's lab. I am from Spain, where I got my BS in Biology and my PhD. I received my doctoral training at the University of Murcia, with Professor Rosa M. Ruiz-Vazquez. My research focused on the RNA silencing pathway in the basal and pathogenic fungus Mucor circinelloides. Just when I became an undergraduate student in the same lab, they had started that new line of research, and I loved it! So since then I've tried to unravel the complex mechanism of RNA silencing in Mucor. The main scientific achievements of my PhD were: 1) reveal that two distinct RNA-dependent RNA polymerases are required for initiation and amplification of RNA silencing, and 2) that RdRP1 (RNA-dependent RNA polymerase 1) is essential, besides Dicer2, for the production of endogenous small RNAs (esRNA) in Mucor circinelloides. Those esRNAs target the mRNA of protein coding genes from which they are produced, expanding the range of esRNAs in eukaryotes and revealing a new role for esRNAs in fungi.

After I finished my PhD, I spent some time teaching Genetics trying to show young (and not so young) students the amazing world hidden in the genetic code. I joined Dr. Heitman's lab in February 2012, and I've had the opportunity of continuing my research in the RNA silencing pathway both in Mucor circinelloides and Cryptococcus.


Billmyre RB, Calo S, Feretzaki M, Wang X and Heitman J. 2013. RNAi function, diversity, and loss in the fungal kingdom. Chromosome Res 21:561–572.

Calo S , Billmyre RB, and Heitman J. 2013. Generators of phenotypic diversity in the evolution of pathogenic microorganisms. PLOS Pathogens’ Pearls 9:e1003181.

Lee SC, Li A, Calo S , and Heitman J. 2013. Calcineurin plays key roles in the dimorphic transition and virulence of the human pathogenic zygomycete Mucor circinelloides. PLOS Pathogens 9:e1003625.

Calo S, Nicolás FE, Vila A, Torres-Martínez S and Ruiz-Vázquez RM. 2012. Two distinct RNA-dependent RNA polymerases are required for initiation and amplification of RNA silencing in the basal fungus Mucor circinelloides. Molecular Microbiology. 83(2):379–394.

Nicolás FE, Moxon S, de Haro JP, Calo S, Grigoriev IV, Torres-Martínez S, Moulton V, Ruiz-Vázquez RM & Dalmay T. 2010. Endogenous short RNAs generated by Dicer 2 and RNA-dependent RNA polymerase 1 regulate mRNAs in the basal fungus Mucor circinelloides. Nucleic Acids Research 38:5535-5541.

de Haro JP, Calo S, Cervantes M, Nicolás FE, Torres-Martínez S, Ruiz-Vázquez RM. 2009. A single dicer gene is required for efficient gene silencing associated with two classes of small antisense RNAs in Mucor circinelloides. Eukaryotic Cell 8:1486-1497.

Nicolás FE, Calo S, Murcia-Flores L, Garre V, Ruiz-Vázquez RM & Torres-Martínez S 2008. A RING-finger photocarotenogenic repressor involved in asexual sporulation in Mucor circinelloides. FEMS Microbiology Letters 280:81-88.

[Back to Heitman lab]