Janis E. Lochner

Dr. Robert B. Pamplin, Jr., Professor of Science, Biochemistry

department: Chemistry
office: 223 Olin Center
phone: 503-768-7538
e-mail: lochner@lclark.edu
Web: http://www.lclark. edu/~lochner/

Degree: Ph.D. 1981 Oregon Health Sciences University

At Lewis and Clark College Since: 1982

As a biochemist, my studies focus on the molecular logic of the living state. In recent years, I’ve been most intrigued by chemical communication within the nervous system. The rich diversity of communication in the nervous system arises from the regulated secretion of chemical messengers at the synapse. Synapses are the gateways through which messages are sent and lines of communication established. Interestingly, synapses are not static but rather can be stably reconfigured. During processes such as long-term memory formation, neuronal architecture is modified.

How does architectural remodeling occur at the molecular level? Results derived from several recent studies suggest that certain proteins facilitate the process by functioning as molecular scalpels. These molecular scalpels are strategically released at the synapse and disrupt existing molecular contacts thereby allowing growth and accompanying changes in the number and pattern of synaptic connections. Several lines of evidence suggest that the protein, tissue plasminogen activator (tPA), serves as a modulator of learning-related synaptic plasticity. To better understand the molecular determinants of synaptic plasticity, we are trying to localize tPA in hippocampal neurons and study the activity-dependent secretion of tPA from synaptic structures.

Our system for visualizing tPA in neuronal cells makes use of the tools of recombinant DNA technology and, surprisingly enough, a gene derived from the jellyfish Aquorea victoria. Why a jellyfish gene? This particular jellyfish gene codes for a protein with a novel property; the protein fluoresces or glows thereby permitting visualization by fluorescence microscopy. The gene for the jellyfish protein is appended to the gene encoding tPA. After introducing this chimeric gene into cells, time-lapse images of the tPA/GFP protein are taken using high-resolution fluorescent microscopy. Movies showing the trafficking of tPA/GFP in hippocampal neurons can be viewed at this site.