Title:   NSF/Tokyo Report: A Survey of Laboratories Involved in Plant
           Biochemistry Research in Japan

Date:    November 12, 1997


The National Science Foundation's offices in Tokyo and in Paris periodically
report on developments abroad that are related to the Foundation's mission.
These documents present facts for the use of NSF program managers and policy
makers; they are not statements of NSF policy.

Special Scientific Report #97-37 (November 4, 1997)

A survey of laboratories involved in plant biochemistry research in Japan


Dr. Eliot M Herman, former Program Director for Cell Biology at the National
Science Foundation, prepared the following report.  Dr. Herman recently
returned full-time to his position as Plant Physiologist with the Agricultural
Research Service of the USDA.  Dr. Herman visited Japan from September 15,
1997 to October 8, 1997 as a Visiting Research Fellow (short-term) under the
sponsorship of the Japan Society for the Promotion of Science (JSPS).
Professor Takao Minamikawa of the Department of Biology at Tokyo Metropolitan
University, Tokyo, Japan served as host scientist for Dr. Herman.  Dr. Herman
may be reached via email at: eherman@asrr.arsusda.gov.

1. Introduction

At the invitation of JSPS, I completed a trip to visit Japanese universities
and research institutes from September 15, 1997 to October 8, 1997. I am
grateful to the JSPS for its kind and generous fellowship invitation. I
greatly enjoyed my visit which expanded my understanding of Japanese
contributions in the plant sciences. During my fellowship I visited five
universities and research institutes at which I presented seminars on research
from my laboratory and I had numerous discussions with faculty and students. I
also engaged in individual research in collaboration with my host Professor
Minamikawa that brings a project to completion. These activities are described
in additional detail in subsequent paragraphs.

2. Travel and visits

I visited Hokkaido University in Sapporo from September 18 to 21, 1997 where
my host was Professor Satoshi Naito. I am interested in Professor Naito's work
on regulation of storage protein expression and enjoyed discussing research
perspectives with him and the members of his laboratory. During my visit I
made two seminar presentations on "The Accumulation and Disposal of Normal and
Misfolded Storage Proteins" September 19, 1997 and "Ontogeny of Seed Oil Body
Formation" on September 21, 1997. I also visited with other investigators at
Hokkaido University.  I have a research interest in the adaptation of cereals
to abiotic stress and while at Hokkaido University I had the opportunity to
visit the Institute of Low Temperature Science. The Institute is an impressive
facility that offers its investigators world-class facilities well designed
for low temperature research. I had discussions with Professor Shizuo Yoshida
at the Institute of Low Temperature Studies at Hokkaido University and Dr.
Ryozo Imai, a senior research scientist at Winter Stress Laboratory or
Hokkaido National Agricultural Experiment Station. I was particularly
interested in discussing an important observation Professor Yoshida made on
the disassembly of the vacuolar ATPase in response to cold stress in sensitive
plants. I enjoyed my conversations about low temperature stress with both of
these scientists and it is my!
 hope that we will find future interactions or collaborations.

During September 21 through 27, 1997 I remained at Tokyo Metropolitan
University where I worked with members of Professor Minamikawa's laboratory on
our collaborative research project. On September 25, 1997, I presented a
research seminar on the "Cell and Molecular Biology of P34, the Major Soybean
Allergen."

I visited the National Institute for Basic Biology at Okazaki on September 28
to October 1, 1997 where my hosts were Professors Mikio Nishimura and Ikuko
Hara-Nishimura. I have read many excellent papers from their laboratory on the
ontogeny of vacuoles and I am pleased to have had the opportunity to meet with
them, their students and their visiting scientists. I presented a seminar,
"The Accumulation and Disposal of Normal and Misfolded Storage Proteins," on
September 29, 1997.

>From Okazaki I then visited Nagoya University on October 1 to 3, 1997 where
my hosts were Professors Kenzo Nakamura and Masayoshi Maeshima. I am very
familar with their excellent research on vacuole protein targeting and vacuole
biology. I looked forward to meeting Professor Maeshima because as an editor
of Journal of Experiment Botany, I have often asked him to review papers in
his field of expertise. His reviews have proven most useful to me and now that
I have had the chance to meet him I can place his reviews into the context of
a person I know.  On October 1, 1997 I presented a seminar similar to one
presented two days before at Okazaki.

My last visit was to Tsukuba on October 5, 1997. I was particularly interested
in visiting the Rice Genome Research Program where I met with Professor Takuji
Sasaki. During 1996-7 I served at the National Science Foundation as a Program
Director of Cell Biology where I had the opportunity to participate in the
reviewing the progress of the Arabidopsis genome program. Visiting another
leading genome program was both exciting and informative. Professor Sasaki
generously gave me a tour of the facility and explained the accomplishments
and objectives of the program. I greatly enjoyed my visit to this impressive
facility. At the National Agriculture Research Center of the Ministry of
Agriculture at Tsukuba I met with Dr. Masao Ishimoto. Dr. Ishimoto has
conducted research on P34 which is a protein my laboratory discovered and
cloned and was subsequently shown by Japanese scientists to be the major
soybean allergen. We discussed our independent attempts to identify null
germplasm that would be important in selecting hyperallergenic germplasm. We
have both independently found that there does not appear to be a null in the
germplasm diversity. We discussed my plans of using biotechnology to alter the
seed composition to eliminate the allergen that would introduce an important
trait into soybeans.

At each location I visited I made it a point to talk with as many graduate
students as possible. I found the 50 or graduate students that I had the
pleasure of meeting uniformly hard working, excited about their work, and
optimistic about their future. I now understand the challenge they face to
attend graduate school without the support of fellowships available to their
American counterparts. My discussions with the graduate students were
especially rewarding. Many of the students expressed initial reluctance to
speak English out of concern that their mastery was insufficient. However I
found that with a little patience these students soon became comfortable and
freely communicated about their projects. I have learned a great deal about
how science appears from their perspective and this greatly increased my
respect for their efforts and the challenge that students face as they
complete their studies. It is my opinion that Japanese graduate students would
benefit from short-t! erm visits to the US during the course of their studies.
Mr. Takashi Okomoto from Tokyo Metropolitan University has visited my
laboratory to conduct a portion of his doctoral research and his language
ability significantly improved during a months stay. Because English language
is so essential to the careers for Japanese scientists it is very useful to
spend a month or two in the US where their language ability would advance.
This would be especially useful for the best students that are clearly on a
track toward an academic career.

Several faculty asked me how additional contacts and interactions with US
investigators could be accomplished. I emphasized that this requires personal
contact and, under the best circumstances, collaborations. I repeated how much
I enjoyed my own collaboration with Prof. Minamikawa and his students and
emphasized my belief that many other US investigators would benefit and
appreciate similar opportunities. Support for collaborations is available from
both Monbusho and the National Science Foundation. Funds are available to
support the visits of American students to Japan. I believe that American
students would benefit from the opportunity to visit Japan and I have urged
the faculty that I met to make the effort to suggest that American students
visit their laboratories to their colleagues at US universities.

Although most of my time was used for professional activities, I did have the
chance to use a weekend for tourist activities. I visited Nara and Kyoto for
the first time with Professor Minamikawa on September 27 and 28, 1997. These
are wonderful places that I have long wished to visit.

3. Research activity

During the fellowship period I extended the research that was in progress as a
collaboration between Dr. Minamikawas laboratory at Tokyo Metropolitan
University and my laboratory at Beltsville.  This collaboration resulted from
observations that each of our laboratories independently published where I had
been interested in the biological function of ER retention sequences and Dr.
Minamikawa discovered a unique thiol protease (SH-EP) that possesses an ER
retention sequence. My visit afforded us the opportunity to begin to assemble
a manuscript on our work and to interact with the Tokyo Metropolitan
University graduate students working on the project. The research we have
completed indicates a novel use of ER targeting sequences for the purpose of
transient storage of the precursor of SH-EP. A brief summary of the results of
this project are detailed in the following paragraph.

SH-EP is a cysteine protease from germinating mung bean (Vigna mungo)
cotyledons that functions to degrade vacuolar storage proteins to supply
nitrogen and carbon for the early stages of the new plant`s growth. SH-EP
appears to be a typical member of the papain superfamily cysteine proteases
with structural features including a large precursor segment and conserved
structural and active site amino acids. Of the many cysteine proteases that
have been identified in plant, animal and fungal cells only SH-EP and a
closely related bean proteases possess a carboxyterminal ER retention sequence
KDEL found on ER lumen resident proteins. In order to examine the function of
the ER retention sequence we expressed a full-length cDNA of SH-EP and a
minus-KDEL control in sf/9 cells using the bacculovirus system. The
observations on the synthesis, processing and trafficking of SH-EP in sf/9
cells support a model where the KDEL ER-retention sequence is
posttranslationally removed either within the ER or immediately after its exit
from the ER resulting in the accumulation of proSH-EP minus its KDEL signal.
It is this intermediate form that appears to progress through the endomembrane
system and is subsequently processed to form mature active SH-EP. The function
of the KDEL ER-rentention sequence may be to retard the exit of proSH-EP from
the ER leading to its temporary accumulation within the ER making SH-EP with
its KDEL retention sequence a transient zymogen. This pattern of
posttranslational processing in sf/9 cells provides an explaination for
previous results on the carboxyterminal terminal sequencing of mature SH-EP
purified from mung bean seeds which was shown to lack the KDEL. SH-EP with its
KDEL in the seed cotyledon cells may serve to provide a posttranslational
control of vacuole protein degradation by allowing sufficient proSH-EP to be
synthesized and stored to rapidly degrade storage proteins by allowing the
cell to directly regulate the delivery of the stored inactive form of proSH-EP
to its activation site and substrate. The removal of an ER retention sequence
with its potential to regulate protein delive! ry to a functional site and
presents an alternative role for ER retention sequences in addition to its
well established role in maintaining the protein composition of the ER lumen.

I want to close the report of my visit by again thanking the Japanese Society
for the Promotion of Science for its very generous support of my fellowship. I
enjoyed every moment of my visit and I know I have made new friends and
colleagues that will provide many new opportunities in the future.