A tail length modifier gene discovered in the Japanese wild mice (Mus musculus molossinus)

The presence of the t haplotypes in strains derived from the Japanese wild mice (Mus musculus molossinus) was investigated. Crosses between the T/+ heterozygous short tailed mice and five normal tailed molossinus strains (MOL-ANJ, MOA, MOL-NEM, MOM and Mns) produced no tailless mice, indicating that these strains possess no t haplotype. In contrast, tailless mice were produced by a cross between the T/+ heterozygotes and a MOL-NIS strain. Mating experiments showed that the tailless character was due to an interaction between the T gene and an autosomal recessive gene carried by the MOL-NIS strain that expresses the short tail character under the homozygous condition. We have tentatively named this gene brachyury-interacting tail length modifier (btm). It remains to be investigated whether the btm gene is located in the t complex region or in the other locus.     

The effects of sex hormones on the synthesis of prostacyclin (PGI2) by vascular tissues

The effects of estradiol and testosterone on prostacyclin (PGI2) release (measured as 6-keto-PGF1 alpha) by vascular tissues using rat aortic rings and cultured rabbit aortic smooth muscle cells (SMC) were investigated. Aortic SMC were prepared from either explants of atherosclerotic intima or those of normal media. Aortic rings obtained from male and female rats which had been treated with estradiol resulted in increased PGI2 synthesis. Furthermore, PGI2 synthesis by cultured medial SMC was significantly increased in the presence of estradiol (10(-7), 10(-9) M). An increased tendency in PGI2 synthesis was also observed in intimal SMC. On the other hand, aortic rings obtained from female rats treated with testosterone resulted in a significant decrease in PGI2 synthesis. However, aortic rings from testosterone-treated male rats and cultured medial and intimal SMC treated with testosterone (10(-6), 10(-8) M) for 48 hr did not show any significant changes in PGI2 synthesis. We also found greater PGI2 synthesis by intimal SMC compared with that by medial SMC. These results suggest that estradiol and testosterone may have opposite functions in the development of atherosclerosis, that is, estradiol for anti-atherosclerotic and testosterone for atherogenic, by modulating PGI2 synthesis by vascular tissues.     

ATL-derived factor (ADF), an IL-2 receptor/Tac inducer homologous to thioredoxin; possible involvement of dithiol-reduction in the IL-2 receptor induction.

HTLV-I transformed T cells not only express a large number of interleukin-2 receptors [IL-2R/p55(Tac)], but also produce a factor named ATL-derived factor (ADF) that augments the expression of IL-2R/p55(Tac). Based on a partial N-terminal amino acid sequence, complementary DNA (cDNA) clones for human and mouse ADF were isolated and sequenced. Recombinant ADF produced by COS-7 monkey kidney cells showed IL-2R/Tac inducing activity on YT cells, which are sensitive for ADF. ADF mRNA was strongly expressed in HTLV-I(+) T cells lines, but not in inactivated cells (THP-1, unstimulated PBMC). Furthermore, in normal human peripheral blood mononuclear cells, the expression of ADF mRNA was enhanced by mitogens or phorbol myristate acetate, suggesting a possible involvement of ADF in the lymphocyte activation. Homology analysis revealed an unexpected relationship between ADF and dithiol-reducing enzyme, thioredoxin, involved in many important biological reactions such as the conversion of ribonucleotides into deoxyribonucleotides, or the stabilization of glucocorticoid receptors. The biological significance of the generation of a redox potential in lymphocyte activation, and the possible involvement of dithiol reduction in the induction of IL-2R/Tac are discussed.     

Fertility in intersubspecific hybrids of laboratory mice (Mus musculus domesticus) and molossinus mice (M. m. molossinus)

We studied the reproductive performance of F1 and F2 hybrids of laboratory mice (C57BL/6, B6 and BALB/c) and molossinus mice (MOM and Mol-A). The F1 x F1 crosses were fully fertile. In the F2 x F2 crosses, the copulation rate was slightly lower and the pregnancy rate was markedly depressed: only 5 out of 18 copulated females (27.8%) became pregnant in the F2 hybrids derived from the reciprocal crosses of B6 x MOM, and in the F2 hybrids from BALB/c x Mol-A crosses, the pregnancy rate was 51.4% (18/35). This low fertility was attributed mainly to the F2 females, because there was a much lower pregnancy rate (56.5%; 26/46) in the (B6 x MOM)F2 female x B6 male crosses compared with the B6 female x (B6 x MOM)F2 male crosses (80.6%; 26/32). On the other hand, the pregnant F2 females were judged to have normal reproductive ability, based on observations of the numbers of corpora lutea, implantations and live fetuses at day 14 of pregnancy. Apparently there is segregation of fertile and sterile females at the F2 generation, but it remains to be determined how the loss of fertility is brought about in the sterile F2 females.     

The chloroplastchIL gene of the green algaChlorella vulgaris C-27 contains a self-splicing group I intron

ThechiL gene product is involved in the light-independent synthesis of chlorophyll in photosynthetic bacteria, green algae and non-flowering plants. The chloroplast genome ofChlorella vulgaris strain C-27 contains the first example of a splitchiL gene, which is interrupted by a 951 bp group I intron in the coding region. In vitro synthesized pre-mRNA containing the entire intron and parts of the flanking exon sequences is able to efficiently self-splice in vitro in the presence of a divalent and a monovalent cation and GTP, to yield the ligated exons and other splicing intermediates characteristic of self-splicing group I introns. The 5 and 3 splice sites were confirmed by cDNA sequencing and the products of the splicing reaction were characterized by primer extension analysis. The absence of a significant ORF in the long P9 region (522 nt), separating the catalytic core from the 3 splice site, makes this intron different from the other known examples of group I introns. Guanosine-mediated attack at the 3 splice site and the presence of G-exchange reaction sites internal to the intron are some other properties demonstrated for the first time by an intron of a protein-coding plastid gene.     

Purification of a novel UV-damaged-DNA binding protein highly specific for (6-4) photoproduct.

UV damage-specific binding proteins are considered to play important roles in early responses of cells irradiated with UV, including damage recognition in the DNA repair process. We have surveyed nuclear and cytoplasmic proteins which bind selectively to UV-irradiated DNA using an electrophoretic mobility shift assay. We detected four distinct binding activities with different mobilities in fractions separated from HeLa cells by heparin chromatography. Three of them were found in nuclear extracts and one in cytoplasmic extracts. We purified one of the binding factors from nuclear extracts to homogeneity, which was designated NF-10 (the 10th fraction of nuclear extract on heparin chromatography). It migrated as a 40 kDa polypeptide in SDS-PAGE, and bound to UV-irradiated double- stranded DNA but not to unirradiated DNA. The binding pattern of the NF-10 protein to DNA irradiated with UV corresponded to the induction kinetics of (6-4) photoproduct. Removal of (6-4) photoproducts from UV- irradiated DNA by (6-4) photoproduct-specific photolyase diminished the binding of NF-10 protein. These results suggest that the NF-10 protein binds to UV-damaged DNA through (6-4) photoproduct. Immunoblot analysis using a monoclonal antibody revealed that the NF-10 protein was expressed in cell lines from all complementation groups of xeroderma pigmentosum, indicating that the NF-10 protein is a novel UV-damaged-DNA binding protein.     

A physical map and clone bank of the black pine (Pinus thunbergii) chloroplast genome

Black pine chloroplast DNA is 119,707 bp long. The physical map is shown and the genes are listed. Plasmid clones covering the entire DNA sequence have been ordered and available upon request.     

Augmentation of antitumor immunity in regional lymph nodes by local immunotherapy

We have previously reported that the antitumor effect of OK-432, a streptococcal preparation, is markedly augmented when injected intratumorally together with fibrinogen (OK-432/fbg) [1]. In order to elucidate the effects of this immunotherapy on regional lymph nodes (RLN), we carried out both morphological and functional analyses of the RLN from colonic cancer patients treated with OK-432/ fbg. Computer-aided morphometry revealed that the maximal cross-sectional areas and the broadest diameters of the RLN were significantly greater (p<0.01) in patients who had undergone local immunotherapy than in patients who had not. The component structures of RLN, such as sinus, follicle and paracortex, were all enlarged in the OK-432/fbg-treated patients, and necrosis of metastatic tumors was observed. RLN lymphocytes recovered from OK-432/fbg treated patients showed elevated reactivity to phytohemagglutinin (PHA) and the stimulation index was clearly higher than that of control patients. Flow cytometric analysis revealed a predominance of T-cells, especially CD4 subsets, and higher positivity for both CD25 and HLA-DR. Furthermore, RLN lymphocytes killed more effectively K562 and Daudi cells in the patients who had had immunotherapy. These results suggest that the effect of local immunotherapy with OK-432/fbg is not restricted to the site of injection but extends to the lymph nodes, and contributes to tumor regression through the augmentation of cellular immunity.Abbreviations RLN regional lymph node(s) - OK-432/fbg OK-432/fibrinogen solution - PHA phytohemagglutinin - NK natural killer - LAK lymphocyte activated killer