SUMMARY REPORTS OF EXCHANGE SCIENTISTS

(1) Tadatsugu Taniguchi
Institute for Molecular and Cellular Biology
Osaka University

Sponsor and Host Institution:
Professor Jan Vilcek
New York University Medical Center
Dates of Visit: March 20-31, 1985

Summary of Activities
My group has been involved in the elucidation of the structure and regulation mechanism of various lymphokines and their receptors. At New York University, Dr. Vilcek and I discussed and reached an agreement for the collaborative efforts to study the genes whose expression is induced by interleukin-2 (IL-2). I gave a lecture at N.Y.U. on interferon and IL-2 gene regulation. At NIH, I discussed with people in the laboratories of Dr. R. Gallo and Dr. W. Paul (1) the mechanism of IL-2 overproduction in malignant, virus-infected T and B lymphocytes and (2) the cloning of cDNAs encoding B cell growth and differentiation factors. I then visited Dr. R. Tjian at the University of California, Berkeley, for discussion and information exchange about the molecular interaction of promoter DNA sequences and factors in gene regulation of eukaryotes. I also met with Dr. H. Sakano in Berkeley and discussed with him the molecular mechanism of immune regulation. At NIH, I gave a lecture on the IL-2 gene cloning and expression. I also met with Dr. H. Okayama and discussed the gene cloning vector with him.



(2) Toshio Hirano
Division of Cellular Immunology
Institute for Molecular and Cellular Biology

Sponsor and Host Institution:
W. E. Paul, M.D.
Chief, laboratory of Immunology
National Institute of Allergy and Infectious Diseases, NIH
Dates of Visit: January 19 - February 2, 1985

Summary of Activities
We are now investigating the mechanisms involved in the proliferation and differentiation of B cells and the role of c-myc oncogene in B cell activation process. My special interests are what is the nature of B cell growth factor (BCGF) and B cell differentiation factor (BCDF) and how do they function In order to answer these questions, the purification and determination of the structure of these factors are essential.
Dr. W. E. Paul and his colleagues are investigating the activation process of B cells and trying to purify mouse BCGF and clone its gene. They have recently made monoclonal antibody against mouse BCGF and purified BCGF by the monoclonal antibody. We have also purified BCDF to homogeneity. I had a lecture concerning the purification of BCDF at NIH. Dr. Paul and I agreed to exchange purified BCGF and BCDF in order to examine the effects of purified factors on B cell proliferation and differentiation. Nobody has investigated B cell proliferation and differentiation processes by using purified factors; therefore, this is the first trial to examine the true function of BCGF and BCDF.
Dr. L. A. Herzenberg and his colleagues are trying to clone human genes encoding membrane antigens expressed on the surface of lymphocytes. They have recently cloned a gene encoding Leu 2 antigen and determined its structure. The technique they employed is essential for us to clone the genes encoding membrane antigens of B lymphocytes, especially receptor molecule for BCDF. During my visit at Stanford University, I got a lot of information concerning the technique they employed, and I believe that this technique is very useful for our investigations on the receptor for BCDF.
Therefore, the program assisted me in achieving my research, i.e., (1) we agreed to exchange purified BCGF and BCDF and start the collaborative study with Dr. W. E. Paul, and (2) I got a lot of information on the technique on gene cloning suitable for the genes encoding membrane antigens. I believe that my efforts have contributed to progress of the NCI-Japan Cancer Program.



(3) Hiroshi Amanuma, Ph.D.
The Institute of Physical and Chemical Research

Sponsor and Host Institution:
Arifa S. Khan, Ph.D., Senior Staff Fellow
Laboratory of Molecular Microbiology
National Institute of Allergy and Infectious Diseases
National Institutes of Health
Dates of Visit: February 4-24, 1985

Summary of Activities
My research objective has been the elucidation of the molecular mechanism of erythroleukemia induction by Friend spleen focus-forming virus (F-SFFV), an acutely leukemogenic, replication-defective murine retrovirus. The deficient env gene region of F-SFFV codes for a glycoprotein with a 55 kDa molecular weight, and this glycoprotein (gp55) has been implicated as responsible for the leukemic transformation of the F-SSFV-infected erythroid progenitor cells. We previously determined the nucleotide sequence of the env region of the molecularly cloned viral DNA of F-SFFV and found that this region is composed solely of viral env sequences and does not contain cellular sequences.
On this occasion, I visited three laboratories in the United States in each of which the role of env gene or the env-related gene in viral leukemogenesis is being actively investigated.
I at first visited the laboratory of Dr. A. S. khan at NIAID, NIH Bethesda. There I presented a seminar entitled "env-related glycoprotein of Friend spleen focus-forming virus." Dr. khan and I had already started the collaborative research project on the genome structure and expression of certain endogenous retroviruses of AKR mouse. We discussed the biological significance of the apparently deficient env regions of these endogenous viruses, although our nucleotide sequence data revealed that there are no long open reading frames in these regions (manuscript in preparation).
Very recently, Dr. Khan succeeded in detecting the smaller env mRNA in various organs of the uninfected normal inbred mouse. This finding may indicate that the deficient env genes of certain endogenous viruses are expressed into mRNA and that they play some unknown important role. Dr. Khan and I agreed to continue our collaboration.
I then visited the laboratory of Dr. B. Chesebro at the Rocky Mountain Laboratories, NIAID, NIH, Hamilton, Montana. I presented a seminar on the gp55 of F-SFFV. Dr. Chesebro recently found that F-SFFV interferes with the infection of the dualtropic, env-recombinant murine retroviruses, indicating that the gp55 may bind to the cell membrane receptor for these viruses. We discussed that this property of gp55 is important for its leukemogenic function. Dr. Chesebro kindly agreed that he will provide us a panel of monoclonal antibodies against env proteins. These antibodies should be very useful for our future studies.
Lastly, I visited the laboratory of Professor D. Kabat at the Oregon Health Sciences University. Professor Kabat has been interested in the function of gp55 of F-SFFV and an analogous glycoprotein (gp54) of Rauscher SFFV. We discussed our preliminary results and agreed that the clue for understanding the function of gp55 would be obtained by analyzing the viral receptors.
(1) The program provided me with an ample opportunity to exchange important information and to speak extensively with the researchers of the related fields. These activities greatly helped me in directing present research and proposing future studies.
(2) Through this program I could make myself better understood by the researchers of related fields. This in turn made it much easier to have important materials, as well as information, provided by other researchers. I would like to continue my collaboration with those scientists whom I visited.
(3) Through the visit to three laboratories I found that researchers in this field, including myself, are thinking of fairly similar research projects, such as the study on retroviral receptors. I believe this would be a basis for a future collaborative work under the program.



(4) Alan M. Schultz
Immunochemistry Section
Laboratory of Molecular Virology and Carcinogenesis, Frederick Cancer Research Facility, Frederick, Maryland

Sponsor and Host Institution:
Eight host institutions
Dates of Visit: August 25 - September 9, 1984

Summary of Activities
During my stay in Japan, I visited the laboratory of Dr. Yoji Ikawa at RIKEN for 1 week and had discussions with several members of his laboratory, spent one afternoon with Dr. K. Seiki of the National Cancer Institute in Tokyo, and attended the Sixth International Congress of Virology at Sendai. Each of these meetings was helpful and stimulating to me and I think also to my hosts.
The most extensive discussions took place with Dr. Ikawa and his laboratory, who were my official hosts. Dr. Arifa Kahn of NIH was also visiting the laboratory at the same time, so I had the opportunity to participate in the first discussion which she had with them at that time on murine endogenous and MCF-type viruses, since I was also interested in that topic. I had previously shown that the gp69/71 of Rauscher murine leukemia virus was due to the presence of an MCF virus as well as the ecotropic virus and had obtained the first sequence information on murine MCF proteins. Thus, I appreciated the opportunity to discuss with Dr. Amanuma the various endogenous fragmentary genomes in the mouse that he had uncovered.
The following 2 days I spent in discussion with Dr. Nuri Sagata on a topic of mutual interest, bovine leukemia virus (BLV). I brought with me my recently published manuscript with amino acid sequence data for the envelope proteins of BLV, and Dr. Sagata had just completed the entire nucleotide sequence of the viral genome. My protein data allowed him to establish the location and extent of the env gene. It was gratifying to us both that my surface glycoprotein sequence was exactly the same as that predicted from his gene sequence and that our transmembrane protein sequences differed at only one amino acid, suggesting a minor but real difference in the viral strains we each were examining. Sequences of the p24 and p15 gag gene proteins of BLV had already been published from our lab, and this had been useful to Dr. Sagata in the analysis of his genomic sequence in that region. Other laboratories had published studies attempting to define the gag proteins of BLV and had reported finding four candidate gag proteins including a p10 protein, in analogy with other retroviruses. Dr. Sagata's genomic sequence has no place for such a protein, and he was relieved to learn that from my unpublished data on BLV protein purification, our lab felt that there were indeed only three gag Proteins in BLV, as his sequence showed, and that the p10 reported by others was probably a fragment of p24 or p15.
On Friday, August 31, I presented a formal seminar on the purification and structure of BLV gag and env proteins and their relationship to the proteins of other retroviruses.
Dr. Sagata and I also did some sightseeing in Tokyo. I think this time was equally important, for although the BLV discussions and exchanges were stimulating and profitable for both of us, they were somewhat formal and not personal. I think that the aim of the scientific exchange is furthered if the scientists can interact as people and not just fellow laboratory workers. There are cultural and language differences to be bridged, and I think that productive scientific "give and take" of ideas and results will come more naturally in the future if the people have time to become friends.
On the last day at Dr. Ikawa's laboratory, I was joined by Dr. Stephen Oroszlan who brought sequence data from the beginning of pol gene of BLV. The comparison of that data with Dr. Sagata’s sequence was the occasion of some excitement. The reading frames of the gag and pol genes are different in BLV, unlike the mouse, and it is unclear how the BLV pol gene can be expressed. Decisions were made concerning the use of results from Dr. Ikawa’s laboratory in publications from our lab and on the use of our data in publications of Dr. Ikawa’s lab, and plans were made for the exchange of results as we study the expression of gag proteins which we expect to contain sequences encoded by the pol gene.
I spent an afternoon in the laboratory of Dr. Yoshida at the Cancer Institute in Tokyo. In Dr. Yoshida's absence, Drs. Seiki and Watanabe arranged for me to give an impromptu seminar for a small group, where I related the progress of protein studies on HTLV and my particular interest in the myristylation of retroviral-transforming proteines. We discussed the work on HTLV in general, including isolation and sequencing of a macacque genome with high homology to HTLV, which Dr. Watanabe was doing; the identification of a protein encoded by the pX region of HTLV, which Dr. Yoshida would be presenting at Sendai; and some general comparisons between BLV and HTLV. Dr. Seiki was interested in the purification techniques I had developed for the BLV envelope proteins, and it was a very stimulating and beneficial visit.
At the International Virology Congress at Sendai, I presented my talk on myristylated structural and transforming proteins of retroviruses. The presentation by Dr. Yoshida was accompanied by demonstrations from three other laboratories (two Japanese, one American) on the existence and characteristics of the pX HTLV protein. Intriguingly, this protein may begin with the gag gene initiator and consequently also be a myristylated protein. There is considerable interest in this protein, and it was important for me to talk to people from the various laboratories about their results.