Department of Molecular and Cellular Biology Faculty . Dr. Krassimir (Joseph) Yankulov

Dr. Yankulov


Office: SSC 3245
Ext: 56466
Lab: SSC 3203
Ext: 58238


My research studies the molecular mechanisms of DNA replication and the regulation of gene expression. I am also excited by teaching these and other topics that provide the very foundation of our understanding of life. Recently my lab has embarked on the analysis of how and when genes switch on and off as directed by chromatin structure. Our primary goal is to understand these so-called epigenetic mechanisms of gene regulation. The implications of the gained knowledge spans from genetic disease and cancer to immune evasion in malaria and to adaptation of single cell organisms to the environment. 


B.Sc. - Sofia, Bulgaria
Ph.D. - Imperial Cancer Research Fund, London, England


  1. Telomeres: gene repression and genome plasticity.

    Telomeres are repetitive sequences at the ends of eukaryotic chromosomes. They confer the formation of repressive chromatin structures and exert strong gene repression signals. Interestingly, the length of telomeres and their structure have been implicated in longevity and genome stability.

    We use the telomeres of S.cerevisiae to study gene repression and the conversion between repressed and active state of genes. We call these on-off switches. Ongoing studies focus on the possible role of dormant origins of DNA replication and associated factors in the epigenetic convertibility of genes. Using this simple genetically accessible model organism, we are attempting to decipher general principles of gene repression and its links to DNA replication.
  2. DNA replication

    DNA replication is tightly controlled to allow exactly one  round of duplication of the genome in each cell cycle. In eukaryotes, this control is exerted through factors, which confer one single firing of origins of DNA replication. We know reasonably well how these factors operate. However, we do not know how these factors communicate  with the complex chromatin environment in eukaryotic nuclei. Recently we have identified a Histone Acetyl Transferase (GCN5), which strongly stimulates the activity of origins of DNA replication in the yeast S. cerevisiae. Studies on the role of histone acetylation in the assembly of pre-replicative complexes and their firing are under way.

Selected Publications

Jeffery, D., Wyse B., Rehman M.A., Brown G.W., You Y., Oshidari R., Masai H. and Yankulov K. Analysis of Epigenetic Stability and Conversions in S. cerevisiae Reveals a Novel Role of CAF-I in Position-Effect Variegation. Nucl. Acids Res. (2013) in press

Yankulov, K. Dynamics and stability: epigenetic conversions in position effect variegation. Biochem. Cell Biol. 2013; 91, 6-13. (review)

Yankulov, K. Dare to challenge the silence? Telomeric gene silencing revisited. Nucleus 2011; 2, 513-516. (review)

Yankulov, K., and Couto, R. Peer review in class: metrics and variations in a senior course. Biochem Mol Biol Educ 2012: 40, 161-168.

Rehman MA, Wang D, Fourel G, Gilson E, Yankulov K. Subtelomeric ACS-containing proto-silencers act as antisilencers in replication factors mutants in Saccharomyces cerevisiae. Mol. Biol. Cell 2009; 20:631-41.

Complete list


MCB*6340 - Advanced Topics in Molecular Genetics. A graduate course focusing on recent advances in molecular genetics with an emphasis on epigenetics.

MBG*4240 - Applied Molecular Genetics. This is an upper level course on advanced molecular biology techniques.

Graduate Students

Daniel Jeffery (Ph.D.)
Roxanne Oshidary (M.Sc.)
Brandon Wyse (M.Sc.)


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