Genetic materials are one of the most important and fundamental research resources for studying biological phenomena. Scientific need for genetic materials has been increasing and will never cease. Ever since it was established as RIKEN DNA Bank in 1987, the Gene Engineering Division of RIKEN BioResource Center (BRC) has been engaged in the collection, maintenance, storage, propagation, quality control, and distribution of genetic resources developed mainly by the Japanese research community. When RIKEN BRC was inaugurated in 2001, RIKEN DNA Bank was incorporated as one of its six Divisions, the Gene Engineering Division. The Gene Engineering Division was selected as a core facility for the genetic resources of mammalian and microbe origin by the National BioResource Project (NBRP) of the Ministry of Education, Culture, Sports, Science and Technology (MEXT), Japan in 2002. With support from the scientific community, the Division now holds over 3 million clones of genetic materials for distribution. The genetic resources include cloned DNAs, gene libraries (e.g., cDNA and genomic DNA cloned into phage, cosmid, BAC, phosmid, and YAC), vectors, hosts, recombinant viruses, and ordered library sets derived from animal cells, including human and mouse cells, microorganisms, and viruses. Recently genetic materials produced by a few MEXT national research projects were transferred to the Gene Engineering Division for further dissemination. The Gene Engineering Division performs rigorous quality control of reproducibility, restriction enzyme mapping and nucleotide sequences of clones to ensure the reproducibility of in vivo and in vitro experiments. Users can easily access our genetic materials through the internet and obtain the DNA resources for a minimal fee. Not only the materials, but also information of features and technology related to the materials are provided via the web site of RIKEN BRC. Training courses are also given to transfer the technology for handling viral vectors. RIKEN BRC supports scientists around the world in the use of valuable genetic materials.

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The fruit fly, Drosophila melanogaster, is not categorized as a laboratory animal, but it is recognised as one of the most important model organisms for basic biology, life science, and biomedical research. This tiny fly continues to occupy a core place in genetics and genomic approaches to studies of biology and medicine. The basic principles of genetics, including the variations of phenotypes, mutations, genetic linkage, meiotic chromosome segregation, chromosome aberrations, recombination, and precise mapping of genes by genetic as well as cytological means, were all derived from studies of Drosophila. Recombinant DNA technology was developed in the 1970s and Drosophila DNA was the first among multicellular organisms to be cloned. It provided a detailed characterization of genes in combination of classical cytogenetic data. Drosophila thus became the pioneering model organism for various fields of life science research into multicellular organisms. Here, I briefly describe the history of Drosophila research and provide a few examples of the application of the abundant genetic resources of Drosophila to basic biology and medical investigations. A Japanese national project, the National BioResource Project (NBRP) for collection, maintainance, and provision of Drosophila resources, that is well known and admired by researchers in other countries as an important project, is also briefly described.

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Silkworms have played an important agricultural role in supporting Japan’s modernization, and traditionally, Japan has led the world as a repository of silkworm bioresources. The silkworm is a small and highly domesticated insect, which is ideal as a laboratory tool, although it is a bioresource that is relatively infrequently used in experiments at present. In this review, we describe the potential for silkworm resources to contribute to life sciences.

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To collect rat mutations and increase the value of the rat model system, we introduced fancy-derived mutations to the laboratory and carried out genetic analyses. Six fancy rats were shipped from a fancy rat colony in the USA and used as founders. After initial crosses with a laboratory strain, TM/Kyo or PVG/Seac, inbreeding started and 6 partially inbred lines, including 2 sublines, were produced as Kyoto Fancy Rat Stock (KFRS) strains. During inbreeding, we isolated 9 mutations: 5 coat colors, American mink (am), Black eye (Be), grey (g), Pearl (Pel), siamese (sia); 1 coat pattern, head spot (hs); 2 coat textures, Rex (Re), satin (sat); and an ear pinnae malformation, dumbo (dmbo). Genetic analyses mapped 7 mutations to particular regions of the rat chromosomes (Chr): am to Chr 1, sia to Chr 1, sat to Chr 3, Re to Chr 7, g to Chr 8, dmbo to Chr 14, and hs to Chr 15. Candidate gene analysis revealed that a missense mutation in the tyrosinase gene, Ser79Pro, was responsible for sia. From mutant phenotypes and mapping positions, it is likely that all mutations isolated in this study were unique to the fancy rat. These findings suggest that fancy rat colonies are a good source for collecting rat mutations. The fancy-derived mutations, made available to biomedical research in the current study, will increase the scientific value of laboratory rats.

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The aim of this study was to develop and characterize a rat glomerulonephritis model, which progresses to renal fibrosis and renal failure. A single immunization of female WKY rats with more than 10 μg of recombinant α3(IV)NC1 protein caused severe proteinuria followed by progressive increases in plasma creatinine and blood urea nitrogen (BUN) level within 42 days. Sequential histopathological evaluation revealed crescent formation in glomeruli followed by tubular dilation and interstitial fibrosis. Hydroxyproline content and expression of type I collagen and smooth muscle actin genes in the renal cortex increased as renal dysfunction progressed. Furthermore, the TGF-β1 level in the renal cortex also increased. In the evaluation of antinephritic agents in this model, prednisolone and mycophenolate mofetil (MMF) treatment significantly decreased plasma creatinine and BUN, and suppressed renal fibrosis and histological changes involving crescent formation, compared with the vehicle-treated nephritic rats, whereas lisinopril treatment failed to improve renal function and histology. We demonstrated that immunization of female WKY rats with a sufficient dose of recombinant α3(IV)NC1 induces end-stage kidney disease accompanied by renal fibrosis. The relatively short period needed to induce the disease and the high incidence of functional and structural changes were considered a great advantage of this model for clarifying the mechanisms of progressive glomerulonephritis and for evaluating agents used to treat renal failure.

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The central region of the primate retina is called the macula. The fovea is located at the center of the macula, where the photoreceptors are concentrated to create a neural network adapted for high visual acuity. Damage to the fovea, e.g., by macular dystrophies and age-related macular degeneration, can reduce central visual acuity. The molecular mechanisms leading to these diseases are most likely dependent on the proteins in the macula which differ from those in the peripheral retina in expression level. To investigate whether the distribution of proteins in the macula is different from the peripheral retina, proteomic analyses of tissues from these two regions of cynomolgus monkeys were compared. Two-dimensional gel electrophoresis and mass spectrometry identified 26 proteins that were present only in the macular gel spots. The expression levels of five proteins, cone photoreceptor specific arrestin-C, γ-synuclein, epidermal fatty acid binding protein, tropomyosin 1α chain, and heterogeneous nuclear ribonucleoproteins A2/B1, were significantly higher in the macula than in the peripheral retina. Immunostaining of macula sections by antibodies to each identified protein revealed unique localization in the retina, retinal pigment epithelial cells and the choroidal layer. Some of these proteins were located in cells with higher densities in the macula. We suggest that it will be important to study these proteins to determine their contribution to the pathogenesis and progression of macula diseases.

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We attempted to detect natural mutations existing in the Jcl:ICR closed colony of mice which is maintained by random mating. We used ordinary genetic backcrosses to efficiently detect recessive mutations carried by individual mice in the colony. Crosses of DBA/2 females and ICR males were performed to obtain F₁ mice. Four F₁ females randomly selected from each cross were backcrossed to the male parent. More than thirty backcross progeny were obtained from each F₁ female by several deliveries. Phenotypes of the backcross progeny were observed macroscopically at about one month of age. As a result, 18 (26.1%) of 69 Jcl:ICR males carried 11 recessive mutation(s). Based on the phenotypes, the tentative names were abnormal kidney, aplasia of eyelids/hind limb digits, circling, dwarfism, heterotaxy, hind limb paralysis, hydrocephalus, rigidity (or rigor), testicular hypoplasia, tremor, and wobbling. The genes responsible for aplasia of eyelids/hind limb digits and dwarfism were each carried by two males, the genes responsible for hydrocephalus and testicular hypoplasia were each carried by three males and the gene responsible for wobbling by four males. It was strongly suggested that the genes shared by several males originated from an identical mutated gene. Surprisingly, male No. 43 had the responsible genes of abnormal kidneys and testicular hypoplasia, and No. 79 had those of dwarfism and tremor. The results obtained in this study suggest that breeders need to be aware of the presence of natural mutations in their colonies.

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In the case of mice, when the difficulty of a water maze learning task is increased, some animals gradually cease to swim, abandon adaptive learning, and become immobile. We trained 99 male C57BL/6N mice in a pool containing a hidden platform. The pool was surrounded by white featureless walls, and almost all external cues were removed. On the eighth day of escape training, 36 inferior-learners exhibited behavioral despair. The predictive validity of the inferior-learners as a depression model was verified by testing their sensitivity to clinically efficacious antidepressants. The inferior-learners treated with a selective serotonin reuptake inhibitor (SSRI), fluvoxamine, or a serotonin noradrenaline reuptake inhibitor (SNRI), milnacipran, resumed swimming and adaptive learning. Because of facial similarities between inferior-learners and depressive patients and their sensitivity to antidepressant drugs, our experimental method is expected to be an effective tool in basic research on depression.

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