CIMBio Course Fills Urgent Need

By Mika Ono

The Scripps Research Institute's Center for Integrated Molecular Biosciences (CIMBio) was abuzz with activity last week, as some 80 people spilled out of conference rooms, microscopy suites, and laboratories as part of an intensive, nine-day course entitled "A Practical Course in Molecular Microscopy."

"This course in cryo-electron microscopy addresses a desperate need," says Associate Professor Clint Potter. "The field is taking off and there simply aren't many ways to be trained in the technique."

Organized by Potter, Associate Professor Bridget Carragher, and Professor Ron Milligan under the auspices of the National Resource for Automated Molecular Microscopy at CIMBio, the course aims to offer students a thorough grounding in all aspects of molecular structural determination by cryo-electron microscopy.

Forty participants—Ph.D. candidates, postdocs, and a few senior scientists—and 36 instructors —many of whom are pioneers in the field—traveled from labs around the world to attend the course. Dozens of support staff and scientists from Scripps Research also participated.

The schedule of classes was not for the fainthearted.

Students spent mornings in lectures—on topics such as "Fundamentals of Image Analysis and Averaging," "Introduction to 2D Crystal Analysis," and "Imaging: Recording and Assessment." They spent afternoons in hands-on workshops on sample preparation, use of the electron microscope, and evaluation and analysis of the images. They spent evenings in poster sessions, additional workshops, and sessions tailored to address individual research projects.

"These are 13-hour days," notes Potter, "and for some people they're longer, because they stay up late chatting. I'm expecting we'll all look pretty bad by the end of it."

But, as the course progressed, enthusiasm among the participants seemed unflagging.

"I am pretty tired," admitted Gary Ren, a research associate in the Yeager lab, a few days in to the proceedings. "It's incredibly exciting, though. This is a precious time and I want to make the most of it."

Naked and Cold

Why all the interest in cryo-electron microscopy?

The technique sits squarely between the established fields of x-ray crystallography, on the one hand, which can solve protein structures to exquisitely high resolution, and cell biology, on the other, which focuses on the larger picture of where those proteins are in a cell.

"With cryo-EM, we can look at how solved protein structures perform critical tasks within a cell, such as transportation and replication," says Carragher. "That's what the technique is all about from our perspective—putting together the parts of a working machine."

Milligan notes that cryo-electron microscopy is currently the only technique that can be used to directly visualize macromolecular machines within a cell.

"You simply can't grow crystals of things whose conformation changes by the second," he notes. "So, over the last 30 years, methodologies of looking at these pieces frozen in their native state, naked and cold, have developed."

According to Milligan, cryo-electron microscopy has come into its own during the last few years. Many top universities have hired cryo-electron microscopists. Cryo-electron microscopy has been recognized by granting agencies as an important technology. And an increasing number of researchers are trying to break into the field.

"It's a vibrant area," observes Millgan.

While interest in cryo-electron microscopy is burgeoning among scientists worldwide, training opportunities have remained limited. While scientists present papers at conferences, rarely can they address the issues of technique in these forums.

"Conferences are about results, not technique," states Carragher. "In general, [at conferences technique] is just the thing you do in your lab—but sometimes it's what makes the difference between success and failure."

Potter adds, "There's not much [about cryo-EM technique] written down. One of the problems in our field is that there has not been a general protocol. A lot of experimental technique is lore passed from scientist to scientist."

A Course is Born

Up until now, one training ground for cryo-electron microscopy technique has dominated the field—a course held every other year at the European Molecular Biology Laboratory in Heidelberg, Germany.

"Almost everyone in the field started at Heidelberg or has taught there," says Carragher. "Because cryo-EM is complex, it's hard to get started [in it] without going to a course and meeting the people."

In recent years, however, the Heidelberg course has become chronically oversubscribed.

So, the CIMBio team decided to fill the gap with a course of its own, offered in the off years for the Heidelberg course and aimed primarily at scientists in the United States and Pacific Rim to balance the Heidelberg course's European thrust.

The idea for a new course was met with overwhelming support from other researchers in the field. When the team contacted the world's leading cryo-electron microscopists about teaching at the course—for free—all accepted the invitation. Personnel from several of the other national resource centers around the country also offered to give lectures and demonstrations.

Funding to cover the expenses of food, busing, and faculty travel came from both public and private sources. Two National Institutes of Health grants, and a donation from the Agouron Institute supported the venture. Participants paid a registration feel of $350. And several private firms—FEI Co., Gatan Inc., and Tietz Video and Image Processing Systems—also helped out.

"Manufacturers have been very supportive, not only by cutting checks, but also by donating equipment and resources," says Potter.

To hear Potter and Carragher tell it, getting people to apply to the course was probably the easiest part of the process.

"We did very little advertising and got a huge response," says Potter. "We put out one e-mail, received 80 applications, and closed the course in June."

The team originally planned to offer 24 places to those most qualified and most needing the training, but, as Carragher admits, "We weren't very good at saying 'no,' so we squeezed up to 36 by the time the course started and then added four more on the first day!"

CIMBio Can Take It

Potter, Carragher, and Milligan's time during the last two months has been dominated by grappling with arranging the logistics of the course.

"It's been a lot of work," notes Potter.

"A huge effort involving many people," seconds Carragher. "We are grateful to the dozens of support staff and scientists at Scripps who generously donated their time and attention."

Thankfully, the CIMBio building at Scripps Research, which opened early last year, has also made their job a little easier.

"Having so many people in your building for 10 days is no joke," says Carragher. "There aren't many buildings that can take it, but CIMBio can. We have a fantastic microscopy suite—one of the best there is."

In the CIMBio Building are six rooms for microscopes, which are mounted on three-foot-thick concrete slabs isolated from the building's foundation to protect the instrumentation from vibrations. The rooms are climate-controlled with low humidity to prevent contamination of samples by water vapor, and are sound-proofed so that outside noise does not cause minute movement.

"We also have a large lecture room, facilities with computers, and lab space with an open configuration," says Potter. "We had this course in the back of our minds when we were designing the building."

After nine long days of lectures, workshops, microscopy work, and discussions, however, the building was becoming part of the background for most of the course participants.

The value of what they were learning, however, was still front and center.

"The course has been offering a wonderful survey of current methods, excellent exposure to ground-breaking research, and an ideal combination of lectures and hands-on experience," said one participant, too shy to be identified by name. "In addition, there's been a very nice atmosphere to get to know each other."

"Some of the instructors here are pillars of the field," enthused Christopher Ackerson, a Ph.D. candidate at Stanford University. "The roster is impressive."

One instructor, Alok Mitra from the University of Aukland, added, "The students have been surviving—and that is saying a lot!"

So, was all the work organizing the course worthwhile?

Potter didn't hesitate with a resounding "Yes!"

Carragher seemed to agree, pointing to the remarkable cross-fertilization and interaction that had taken place among the scientists: "At least one exchange will result in a publication in the near future!"

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Investigators Ron Milligan (left), Clint Potter, and Bridget Carragher organized the recent course on cryo-electron microscopy. "We did very little advertising and got a huge response," says Potter. Photo by Kevin Fung.