M. Jade Zee
zee@uoneuro.uoregon.edu
University
of Oregon
Institute of Neuroscience
1254 University of Oregon
Eugene, OR 97403-1254 USA
http://www.neuro.uoregon.edu/weekslab/website/jade.htm
Advisors:
Dr.
Janis
C. Weeks, Institute of Neuroscience
Dr.
Patrick C. Phillips, Program in Ecology & Evolution
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Jade earned her Ph.D. in 2004 and will begin a postdoctoral position in the lab of Andy Bass at Cornell University in the Fall
Research Interests
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During metamorphosis of the hawkmoth, Manduca sexta, the central nervous system undergoes dramatic remodeling to accommodate changes in body structure and behavior. The neural remodeling is regulated by steroid hormones called ecdysteroids and includes the segment-specific, programmed cell death (PCD) of accessory planta retractor (APR) motoneurons and their target muscles (APRMs) which control movements of the larval prolegs. The prepupal peak of ecdysteroids causes APRs and APRMs to undergo cell-autonomous PCD in dissimilar segmental patterns. APRs and APRMs in abdominal segments 5 and 6 (A5 and A6) die at pupation. APRs and APRMs in A2 and A3 survive and are respecified to circulate hemolymph in the developing wings and legs during the pupal stage. In A4, the APRs survive but the APRMs degenerate and are replaced by new abdominal extensor muscles (Weeks and Ernst-Utzschneider, 1989).
The cell-autonomous response of APRs and APRMs to ecdysteroids indicates that the motoneurons and muscles have intrinsic segmental identities. To explore this issue, I am examining the metamorphic fate of a homologous neuromuscular system in the domesticated silkmoth, Bombyx mori. Segmentation genes are better characterized in B. mori than in M. sexta and mutants are available. Surprisingly, the putative APR homologs in wild-type B. mori survive until adulthood in all abdominal segments while the putative APRM homologs show a segment-specific pattern of PCD different from that in M. sexta. Specifically, B. mori APRMs survive in A1 and A2 while M. sexta APRMs survive in A2 and A3. During domestication, B. mori has been selected for flightlessness and its wings are one segment shorter in pupae and are nonfunctional in adults. I have determined that APRMs in B. mori pupae circulate hemolymph in the developing appendages and have tested the hypothesis that the anteriorward shift of retained APRMs is associated with the reduced wing phenotype. To this end, I have examined B. mandarina, the wild silkmoth ancestor of B. mori as well as other silkmoths with functional adult wings (Hyalophora cecropia and Actias luna) and found that APRMs were retained in pupal segments A2 and A3, the same pattern as in M. sexta.
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Publications
Zee, M.C., Roberts, W.M., and Weeks, J.C. (2004) Membrane curents measured during steroid-mediated programmed cell death of a motoneuron. Soc. Neurosci. Abstr. submitted.
Kinch, G.L., Hoffman, K.L., Rodrigues, E.M., Zee, M.C. and Weeks, J.C. (2003) Steroid-triggered programmed cell death of a motoneuron is autophagic and involves structural alterations in mitochondria. J. Comp. Neurol. 457:384-403.
Zee, M.C., Hoffman, K.L. and Weeks, J.C. (2003) Steroid-mediated
neuronal death: protection by elevated potassium and the role of ionic currents. Soc. Neurosci. Abstr. 29:355.5.Zee, M.C. and Weeks, J.C. (2003) Segment-specific fate of a larval neuromuscular system during metamorphosis differs in two families of Lepidoptera.
Brain, Behavior Evol. 62:168-174.Zee, M.C. and Weeks, J.C. (2001) Developmental change in the steroid hormone signal for cell-autonomous, segment-specific programmed cell death of a motoneuron. Dev. Biol. 235(1): 45-61.
Gruol, D.J., Vo, Q.D. and Zee, M.C. (1999) Profound differences in the transport of steroids by two mouse P-glycoproteins. Biochem. Pharmacol. 58(7): 1191-1199.
Simerly, R.B., Zee, M.C., Pendleton, J.W., Lubahn, D.B. and Korach, K.S. (1997) Estrogen receptor-dependent sexual differentiation of dopaminergic neurons in the preoptic region of the mouse. Pro. Natl. Acad. Sci. 94: 14077-14082.
Gu, G., Rojo, A.A., Zee, M.C., Yu, J. and Simerly, R.B. (1996) Hormonal regulation of CREB phosphorylation in the anteroventral periventricular nucleus. J. Neurosci. 16(9): 3035-3044.
Simerly, R.B., Carr, A.M., Zee, M.C. and Lorang, D. (1996) Ovarian steroid regulation of estrogen and progesterone receptor messenger ribonucleic acid in the anteroventral periventricular nucleus of the rat. J. Neuroendo. 8: 45-56.
Gruol, D.J., Zee, M.C., Trotter, J. and Bourgeois, S. (1994) Reversal of multidrug resistance by RU 486. Cancer Res. 54: 3088-3091.