Mailing Address:
University of California at Berkeley
Dept. of Integrative Biology
3060 VLSB #3140
Berkeley, CA 94720-3140
Lab TEL (510) 643-6227
FAX (510) 643-5022
Email: mariov[at]berkeley.edu
Research Summary
My current work focuses on the evolution of Dorsoventral (DV) patterning mechanisms in arthropods using the amphipod system Parhyale hawaiensis. While some aspects of DV patterning are thought to be conserved throughout the bilaterian clade (which includes humans, flies, snails, etc.), it is also clear that the expression and regulatory circuitry of specific genes can change significantly over much smaller evolutionary distances.
For example, in bilaterians, DV patterning typically involves the localized secretion of Bone Morphogenetic Proteins (BMPs) and their antagonists on opposing sides of the embryo. In the fruit fly Drosophila melanogaster, a nuclear activity gradient of the Dorsal protein establishes the expression of the BMP protein decapentaplegic (dpp) in a dorsal domain and the BMP antagonist short-gastrulation (sog) in a ventral domain. BMP antagonism specifies the neurogenic ectoderm, while cells of the ventral midline play a subsequent role in nervous system patterning by secreting the EGF ligand Spitz.
Using laser microsurgery in developing Parhyale embryos, I have shown that the Parhyale ventral midline plays a more central role in DV patterning by inducing ventral cell fates in the surrounding tissue. In the absence of ventral midline cells, embryos are dorsalized; they fail to generate central nervous system and the normally bilateral limb buds are fused ventrally. In addition, there is no evidence that the Dorsal protein gradient present in Drosophila plays a role in early Parhyale development. More recently, I have been studying the molecular mechanisms underlying the inductive properties of the Parhyale ventral midline. Specifically, I am interested in the possibility that the midline is a localized source of a BMP antagonist such as sog. This work will ultimately provide a new basis for understanding the evolution of the DV patterning system seen in insects such as Drosophila.
Education
August 2003 – May 2009
Ph.D. Molecular and Cell Biology
University of California, Berkeley
Advisor: Dr. Nipam H. Patel
September 1998 – September 2002
B.S. Biochemistry
University of Massachusetts, Amherst
Phi Beta Kappa, Summa Cum Laude
Fellowships and Scholarships
- GOP fellowship (UC Berkeley), August 2003 – July 2006
- Chancellor’s Award Scholarship (UMASS Amherst), Sept. 1998 – May 2002
Additional Research Experience
Undergraduate Researcher, Sept. 2001 – Sept. 2002
University of Massachusetts, Amherst
Advisor: Dr. David J. Gross
Studied EGF signaling in bovine cumulus cells
Teaching Experience
Fall 2004, Graduate Student Instructor
MCB 130: Cell Biology
University of California, Berkeley
Spring 2006, Graduate Student Instructor
MCB 130L: Cell Biology Lab
University of California, Berkeley
Other Activities
Integrating Evolution, Development, and Genomics (IEDG 2008) conference
Co-organizer
NIPAM H. PATEL
(LEFT) Wild-type expression of Ph-Distal-less-e (Ph-Dll-e, dark purple) and Ph-orthodenticle-1 (Ph-otd-1, red) in a stage 17 Parhyale hawaiensis embryo. Ph-otd-1 is expressed in ventral midline cells of the developing ectoderm while Ph-Dll-e marks the presumptive appendages. (RIGHT) Midline cells corresponding to three adjacent segments were ablated by laser microsurgery, causing aberrant DV patterning in the surrounding ectoderm. The presumptive appendage buds are fused ventrally in the segments lacking midline and the presumptive neurogenic ectoderm fails to form.
