Aimee Jaramillo-Lambert, Ph.D.

Research Interests

During sexual reproduction, haploid gametes (i.e. eggs and sperm) are generated from diploid precursors through the specialized cell division of meiosis. Meiosis reduces ploidy by following one round of DNA replication with two rounds of chromosome segregation (MI and MII respectively). In MII sister chromatids segregate from each other similarly to mitosis; but in MI, it is the homologs that segregate, which requires pairing, synapsis, and recombination. These events must be tightly regulated to ensure the accurate segregation of chromosomes. Perturbations in chromosome segregation can compromise basic cellular functions leading to infertility, progeny inviability, birth defects, and cancer.

Type II DNA topoisomerases are enzymes that play a crucial role in chromosome fidelity by disentangling topological problems that arise in double stranded DNA. The role of Topo II in mitosis has been well defined. Topo II alleviates DNA entanglements that are generated during replication, transcription, sister chromatid separation, and recombination by creating transient double-stranded breaks in DNA. Due to their critical roles in mitosis, topoisomerases are important chemotherapy targets for cancer patients. Topo II enzymatic inhibitors lead to DNA damage that kills cancer cells. However, these inhibitors are highly toxic, can lead to secondary tumors, and cause both male and female infertility. Topo II inhibitor-induced infertility suggests that, in addition to mitosis, these enzymes play critical roles in meiosis. Indeed, studies in mammals, yeast, and Drosophila found that Topo II plays a role in homologous chromosome segregation at MI. In addition, Topo II has been implicated in chromosome structure and condensation in both mitosis and meiosis. However, key questions remain unanswered: 1) Exactly when and how does Topo II interact with the complex chromosome structure and proteins that are required to pair and segregate homologs (synaptonemal complex, recombination proteins, condensins, and cohesins)? and 2) How is Topo II regulated during both meiotic divisions?

Current Projects

Utilizing the unique structural organization of the C. elegans germ line and a combination of cell biological, genetic, and biochemical approaches my lab is:

  • Testing for genetic interactions between top-2 and meiotic chromosome components.
  • Investigating the role of TOP-2 in chromosome structure.
  • Identifying the components required to regulate TOP-2 during meiosis.

Research Group

  • Nirajan Bhandari (Doctoral Graduate Student)
  • Tommy Wilmoth (Masters Graduate Student)
  • Dina Collins (Lab Research Assistant)

Selected Publications

  1. Jaramillo-Lambert, A., A. Fabritius, T.J. Hansen, H.E. Smith, and A. Golden, 2016. The identification of a novel mutant allele of topoisomerase II in C. elegans reveals a unique role in chromosome segregation during spermatogenesis. Genetics 204(4): 1407-1422.
  2. Smith, H.E., A.S. Fabritius, A. Jaramillo-Lambert, and A. Golden, 2016. Mapping Challenging Mutations by Whole-Genome Sequencing. G3: Genes, Genomes, Genetics. 6(5): 1297-304.
  3. Jaramillo-Lambert, A., A. Fuchsman, A. Fabritius, H. Smith, and A. Golden, 2015. Rapid and Efficient Identification of Caenorhabditis elegans Legacy Mutations Using Hawaiian SNP-Based Mapping and Whole-Genome Sequencing. G3: Genes, Genomes, Genetics. 5(5): 1007-19.
  4. Jaramillo-Lambert, A., J. Hao, H. Xiao, Y. Li, Z. Han, and W. Zhu, 2013.  Acidic nucleoplasmic DNA-binding protein (And-1) controls chromosome congression by regulating the assembly of CENP-A at centromeres.  J Biol Chem. 288(3): 1480-1488.
  5. Li, Y., H. Xiao, C. de Renty, A. Jaramillo-Lambert, Z. Han, M.L. Depamphilis, C. J. Brown, and W. Zhu, 2012. The involvement of acidic nucleoplasmic DNA-binding protein (And-1) in the regulation of pre-replicative complex (pre-RC) assembly in human cells.  J Biol Chem. 287(51): 42469-42479.
  6. Li, Y., A. N. Jaramillo-Lambert, Y. Yang, R. Williams, N. H. Lee, and W. Zhu, 2012.  And-1 is required for the stability of histone acetyltransferases Gcn5. Oncogene. 5: 643-652.
  7. Li, Y., A. Jaramillo-Lambert, J. Hao, Y. Yang, and W. Zhu, 2011. The stability of histone acetyltransferase general control non-derepressible (Gcn) 5 is regulated by Cullin4-RING E3 ubiquitin ligase. J Biol Chem. 48: 41344-52.
  8. Jaramillo-Lambert, A., Y. Harigaya, J. Vitt, A. M. Villeneuve, and J. Engebrecht, 2010.  Meiotic errors activate checkpoints that improve gamete quality without triggering apoptosis in male germ cells. Curr. Biol. 20: 2078-2089.
  9. Jaramillo-Lambert, A and J. Engebrecht, 2010.  A single unpaired and transcriptionally silenced X chromosome locally precludes checkpoint signaling in the Caenorhabditis elegans germ line. Genetics 184: 1-16.
    Issue Highlight: Genetics March 1, 2010 vol. 184 no. 3
  10. Jaramillo-Lambert, A., M. Ellefson, A. M. Villeneuve, and J. Engebrecht, 2007.  Differential timing of S phases, X chromosome replication, and meiotic prophase in the C. elegans germ line. Dev. Biol. 308: 206-221.

Assistant Professor

Phone: (302) 831-7045


Office: 321 Wolf Hall


  • B.S. - University of California, Davis
  • Ph.D. - University of California, Davis
  • Postdoctoral - The George Washington University Medical Center
  • Postdoctoral - National Institute for Diabetes and Digestive and Kidney Diseases, National Institutes of Health