University of California, Berkeley
Dept. of Integrative Biology
3060 VLSB #3140
Berkeley, CA 94720-3140
Lab phone: 510/643-4201
Fax: 510/643-5022
Email: mmodrell[at]berkeley.edu
Arthropods exhibit a wide diversity of early embryonic cleavage patterns. For instance, Drosophila develops in a syncytial environment where positional information is conveyed by maternal and zygotic gradient systems. However, many organisms develop in a cellular environment, whereby cell to cell interactions and asymmetric distribution of determinants are required to provide instructional cues. My current research projects involve studying early developmental processes occurring in the malacostracan amphipod, Parhyale hawaiensis, using both comparative embryological approaches coupled with molecular and functional approaches.
Parhyale hawaiensis, an amphipod crustacean, displays total (holoblastic) cleavage during early embryogenesis, and we hope to determine how tightly cell lineage and cell fates are coupled in this species. In Parhyale, the first two divisions are radial, total, and slightly asymmetrical. The third division is highly asymmetric and produces an embryo that consists of four macromeres and four micromeres. Lineage studies performed at the eight-cell stage demonstrate that each cell normally contributes to only one of each of the germ layers (Gerberding et al, 2002). However, it is not known if these cells are specified or determined at this early stage. Cell ablations are a classical method for addressing how lineage is coupled to cell fate, and utilizing this approach at the eight cell stage, we find that there is much regulation which occurs between lineage restricted equivalency groups that give rise to the germline, mesoderm, and ectoderm. In addition, the molecular mechanisms involved in establishing the cell fate pattern in Parhyale are unknown. Therefore, we have taken a candidate gene approach to address this question. Armadillo/b-catenin is one such gene, as it is known to be involved in setting up cell fates in different organisms in a variety of cellular contexts. The Partioning-defective genes (Par) are another such group of genes that are involved in establishing embryonic polarity and cellular asymmetries in several organisms. I am currently characterizing the role of these genes in Parhyale development by in situ hybridization and immunohistochemistry. Additional ablation experiments and mis-expression/knockdown experiments should further reveal the mechanisms behind asymmetric cell division and cell fates in Parhyale.
Publications:
Lewis, J.L., Bonner, J., Modrell, M., Ragland, J., Moon, R.T., Dorsky, R.I., and Raible, D.W. (2004) Reiterated Wnt signaling during zebrafish neural crest development. Development 131: 299-1308.
Lister, J.A., Cooper, C., Nguyen, K., Modrell, M., Grant, K.,and Raible, D.W. (2005) Zebrafish Foxd3 is required for development of a subset of neural crest derivatives. Developmental Biology. 290(1): 92-104.
Svensson, E. C., Wilk, J., Dale, R. M., and Modrell, M. (2005) "The role of the transcriptional co-repressor FOG-2 in cardiac development" in Cardiovascular Development and Congenital Malformations. (Artman, M., Benson, D.W., Srivastava, D., and Nakazawa, M., eds), Blackwell Publ. Oxford. pp125-127.
Talks:
March 2006
St. Judes National Graduate Student Symposium, Memphis, TN
“Cell Fate Specification in the amphipod crustacean, Parhyale hawaiensis”
Melinda S Modrell, Alivia L Price, Roberta Hannibal, and Nipam H Patel
Nov 2005
Molecular and Cellular Biology Retreat, Tahoe, CA
“Cell Fate Specification in the amphipod crustacean, Parhyale hawaiensis”
Melinda S Modrell, Alivia L Price, Roberta Hannibal, and Nipam H Patel
June 2005
Richard B. Gump South Pacific Research Station, Moorea, Tahiti
“Embryonic body patterning and segmentation of the amphipod crustacean, Parhyale hawaiensis”
Alivia L Price, Melinda S Modrell, Kira O’Day, and Nipam H Patel
Posters:
June 2006
Integrating Evolution, Development, and Genomics Conference, Berkeley, CA
Jan 2006
Society for Integrative and Comparative Biology (SICB) Meeting, Orlando, FL
July 2005
Society of Developmental Biology Conference, San Francisco, CA
Nov 2003
Genetics and Development Biology Retreat, Asilomar, CA
Education:
PhD candidate (expected graduation date: Dec 2007)
University of California, Berkeley
Department of Integrative Biology
Nipam H Patel, Advisor
August 2003-present
Embryology Course
Marine Biological Laboratories, Woods Hole, MA
Richard Harland and Joel Rothman, Course Directors
June-July 2004
M.S. in Developmental Biology
University of Chicago
Committee on Developmental Biology
Nipam H Patel, Advisor
September 2001-June 2003
B.S. in Zoology, Minor in Classical Studies
University of Washington, Seattle
August 1994-May 1998
Additional Research Experience:
Research Technician, 1998-2001
University of Washington, Seattle
Supervisor: Dr. David W. Raible, Assistant Professor, Dept. of Biological Structure
Project: Characterization of FoxD3 expression and function during Zebrafish neural crest development.
Undergraduate Researcher, 1997-1998
University of Washington, Seattle
Advisor: Dr. David W. Raible, Asst. Professor, Dept of Biological Structure
Project: Expression and molecular analysis of Zebrafish Eyes absent (eya) genes.
Teaching Experience:
Fall, 2006, Graduate Student Instructor
MCB 142/IB 163: Survey of Genetics
University of California, Berkeley
Spring, 2006, Graduate Student Instructor
MCB 131: Developmental Biology
University of California, Berkeley
Summer, 2006, Teaching Assistant
Embryology: Concepts and Techniques in Modern Developmental Biology
Marine Biological Laboratories, Woods Hole, MA
