Jennifer Head
jhead@oimb.uoregon.edu

University of Oregon
Oregon Institute of Marine Biology
P.O. Box 5389
Charleston, OR 97420 USA

Advisors:
Dr. Richard Emlet, Institute of Marine Biology
Dr. John H. Postlethwait, Institute of Neuroscience

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Research Interests

The focus of my research is a transcription factor called hypoxia inducible factor-1 (HIF-1). HIF-1 is a heterodimer consisting of α and β subunits, where HIF-1β is expressed constitutively and independently of ambient oxygen tensions, and HIF-1α  can not be detected unless the system is hypoxic. A HIF-1 system has been identified in several vertebrate systems and has also been well characterized in Drosophila. HIF-1 participates in the both acute and acclimatory responses to low oxygen in humans by upregulating genes involved in abrogating the negative physiological consequences associated with hypoxia. An example of such a system is the upregulation of the glycoprotein hormone Erythropoietin (EPO) by HIF-1. HIF-1 mediates the acute responses by inducing EPO and the acclimatory responses by increasing overall erythrocyte production with the goal of expanding erythrocyte mass, thus increasing the amount of hemoglobin, and therefore bound oxygen in circulation, a process known as erythropoiesis.

With regard to many aquatic crustaceans, their environment is far from homeostatic, some experiencing significant and frequent fluctuations in such conditions as salinity, temperature and oxygen availability . Most crustaceans undoubtedly experience hypoxia on a more frequent basis than do humans and yet very little is known about the mechanisms underlying hypoxia stress responses and tolerance in crustaceans. It has previously been shown that some crustaceans increase the concentration of their oxygen transport protein (hemocyanin) in response to hypoxia (Mangum, 1997), as well as differentially regulating the subunits of the oxygen carrier in order to change the inherent affinity of the protein for oxygen at low oxygen tensions (Mangum, 1997, Kimura 1999). The mechanism responsible for upregulating hemocyanin and the differential regulation of its various subunits is still a mystery. It is also unknown whether crustaceans have a HIF-1 system to cope with the hypoxia that they undoubtedly experience in their ambient environment. Thus, the goal of my research is to search for and characterize the HIF-1 system in crustaceans, as well as to determine its role in the upregulation of hemocyanin under hypoxic conditions.

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Publications