In eukaryotic cells, the genetic material is packaged into chromatin, and the basic subunit is the nucleosome. Our laboratory seeks to understand how chromatin organization and epigenetics influence gene expression regulation in eukaryotic cells. Many of these mechanisms are very well conserved from yeast to human. In our lab, we have experience in the Saccharomyces cerevisiae model. Moreover, we are interested in understanding highly divergent eukaryotes like trypanosomatids. Particularly, we are focused on the study of Trypanosoma cruzi, due to its epidemiological relevance, and on the study of its host cells. Using biochemistry, molecular biology, gene editing (CRISPR-Cas9), deep sequencing, and bioinformatic analyses, we center our studies on understanding nucleosome organization, epigenetic marks, and their relationship with proteins involved in cell cycle regulation, genome stability, and virulence.
Group members
Lic. Santiago Carena
Becario Doctoral (CONICET)
Lic. María del Rosario López
Becaria Doctoral (CONICET)
Lic. Romina Zambrano Siri
Becaria Doctoral (FCEyN, UBA)
Catalina Machera
Estudiante de Licenciatura en Biología, Universidad Favaloro
Ludmila Dick
Estudiante de Licenciatura en Genética, UNNOBA
Mauro Cheminet
Estudiante de Licenciatura en Biología, FCEyN-UBA
Publications
Determining Histone Posttranslational Modifications Along the Cell Cycle in Trypanosoma cruzi by Flow Cytometry.
María Del Rosario López, Guillermo D Alonso, Josefina Ocampo. Springer Protocols(2026)
Beyond the transcript: chromatin implications in trans-splicing in Trypanosomatids.
Romina Trinidad Zambrano Siri, Paula Beati, Lucas Inchausti, Pablo Smircich, Guillermo Daniel Alonso and Josefina Ocampo*. PLoS One. 2026 Feb 26;21(2):e0343367. eCollection 2026.
Trypanosomatid histones: the building blocks of the epigenetic code of highly divergent eukaryotes.
Josefina Ocampo, Santiago Carena, María del Rosario López, Valentina Sol Vela, Romina Trinidad Zambrano Siri, Sofia Antonella Balestra, Guillermo Daniel Alonso. Biochem J 18 March 2025; 482 (06): 325–340. doi: https://doi.org/10.1042/BCJ20240543
Improving genome-wide mapping of nucleosomes in Trypanosome cruzi
Paula Beati1, Milena Massimino Stepñicka1, Salome C. Vilchez Larrea, Pablo Smircich, Guillermo D. Alonso*, Josefina Ocampo*. Plos ONE 2023 Nov 21;18(11):e0293809. doi: 10.1371/journal.pone.0293809. eCollection 2023.
*co-correspondencia
Interplay among ATP-Dependent Chromatin Remodelers Determines Chromatin Organisation in Yeast
Prajapati HK, Ocampo J*, Clark DJ* (2020)
* co-corresponding authors
doi.org/10.3390/biology9080190
Accessibility of promoter DNA is not the primary determinant of chromatin mediated gene regulation
Chereji RV*, Eriksson PR*, Ocampo J*, Prajapati HK, Clark DJ (2019)
* equal contribution authorship
Genome research, 2019 Dec;29(12):1985-1995 DOI: 10.1101/gr.249326.119
Contrasting roles of the RSC and ISW1/CHD1 chromatin remodelers in RNA polymerase II elongation and termination
Ocampo J, Chereji RV, Eriksson PR, Clark DJ. (2019)
Genome Res. 2019 Jan 25. doi: 10.1101/gr.242032.118
Gcn4 binding in coding regions can activate internal and canonical 5′ promoters in yeast
Rawal Y, Chereji RV, Valabhoju V, Qiu H, Ocampo J, Clark DJ, Hinnebusch AG. (2018)
Molecular Cell 70(2):297-311, Apr 19, 2018
MNase-sensitive Complexes in Yeast: Nucleosomes and Non-histone Barriers
Chereji R*, Ocampo J*, Clark D. (2017)
* Equal contribution
Molecular Cell 65, 578–580, February 2, 2017
The Proto-chromatosome: A Fundamental Subunit of Chromatin?
Ocampo J*, Cui F*, Zhurkin VB, Clark DJ. (2016)
* Equal contribution
Nucleus. 2016 Jul 3;7(4):382-7
The ISW1 and CHD1 ATP-dependent chromatin remodelers compete to set nucleosome spacing in vivo
Ocampo J1, Chereji RV1, Eriksson PR, Clark DJ. (2016)
1 Equal contribution
Nucleic Acid Research. 2016 Jun 2; 44 (10) 4625-35.
A Positive Twist to the Centromeric Nucleosome
Ocampo J and Clark DJ (2015)
Cell Reports. Preview, 2015 Oct 27;13(4):645-6.
Novel Nucleosomal Particles Containing Core Histones and Linker DNA but no Histone H1
Cole HA*, Cui F*, Ocampo J*, Burke TL, Nikitina T, Nagarajavel V, Kotomura N, Zhurkin VB, Clark DJ. (2015)
* Igual contribución de los autores
Nucleic Acids Res. 2015 Sep 22. pii: gkv943
Heavy transcription of yeast genes correlates with differential loss of histone H2B relative to H4 and queued RNA polymerases
Cole HA, Ocampo J, Iben JR, Chereji RV, Clark DJ. (2014)
Nucleic Acids Res. 2014 Nov 10;42(20):12512-22.
Projects
– Understanding chromatin organization and accessibility in trypanosomatids
We seek to elucidate how chromatin is organized genome-wide using second- and third-generation sequencing technologies. Furthermore, we are exploring how the parasite’s epigenetic landscape is modulated in response to oxidative stress.
– Chromatin modifing complexes, epigenetic-marks and cell cycle regulation inTripanosoma cruzi
This research line focuses on the functional characterization of DOT1 and putative SET methyltransferases, alongside the mapping of histone post-translational modifications. Our ultimate goal is to establish a clear connection between these detected epigenetic marks and the molecular machinery involved in their deposition.
Grants
Proyectos de Investigación Científica y Tecnológica 2018 (PICT 2018). ANPCyT, FONCyT. Nro. 00621
“Caracterización de las isoformas TcDOT1a y TcDOT1b e implicancia de la metilación diferencial de H3K76 en los distintos estadios del ciclo de vida de Trypanosoma cruzi”
Proyectos de Investigación Científica y Tecnológica 2020 (PICT 2020). ANPCyT, FONCyT. Nro. 0047
“Metilación diferencial de H3K76 y del ADN en los distintos estadios del ciclo de vida de Trypanosoma cruzi”
Proyectos de Investigación Bianuales para Investigadoras/es Asistentes y Adjuntas/os de reciente ingreso al CONICET PIBBA 2022-2023.
“Implicancias de la metilación diferencial de H3K76 mediada por las isoformas TcDOT1A y TcDOT1B en los distintos estadios del ciclo de vida de Trypanosoma cruzi”
Former members
Lic. Malena Balestrasse
Lic. Valentina Sol Vela
Lic. Sofía Balestra
- Independent Investigator CONICET
- 2002 Biochemist, National University of Rosario
- 2003-2004 Contractor at Parasitology Department of ANLIS “Dr. Carlos G. Malbrán”
- 2010 Dra. de la UBA área Química Biólogica FCEyN UBA
- 2010-2012 Post-doctoral fellow CONICET
- 2012-2018 Post-doctoral (Visiting Fellow) NICHD NIH
- 2015 Fellow Award for Research Excellence (FARE) 2015, NIH
- 2017 Fellow Award for Research Excellence (FARE) 2017, NIH