[Molecular cytogenetic studies of soft tissue tumors]

Molecular cytogenetic studies of 25 cases of soft tissue tumors, including 8 malignant fibrous histiocytomas (MFH), 13 rhabdomyosarcomas (RMS), 3 Ewing's sarcomas (ES) and 1 synovial sarcoma (SS), were performed. Chromosomal analysis showed that of 17 analyzable cases, 15 had chromosomal numerical and structural abnormalities. In RMS, ES and SS consistent chromosomal abnormalities, t(2;13) (q37;q14), t(11;22) (q24;q12) and t(X;18) (p11;q11), respectively, were found, and the remaining 2 had normal karyotypes. Southern blot analysis demonstrated that in 14 cases with matched normal (N) and tumor tissue (T) DNA (5 MFH, 6 RMS, 2 ES, 1 SS), RFLPs changes including loss of allele, partial gene deletion, rearrangement and amplication had occurred at 8 loci (D1S57, D2S44, MYL1-3, D2S3, D13S1, D13S30, ESD and D17S5, respectively). Among these loci, gene changes on D1S57 and D2S44 were found to be shared by MFH, RMS, ES and SS, and D17S5, D2S3 and ESD abnormalities were shared by MFH, ES and SS, as well as by MFH and RMS. These results suggest that a multilocus and multistep process may be involved in the carcinogenesis of MFH, RMS, ES and SS.

A position-dependent transcription-activating domain in TFIIIA

Transcription of the Xenopus 5S RNA gene by RNA polymerase III requires the gene-specific factor TFIIIA. To identify domains within TFIIIA that are essential for transcriptional activation, we have expressed C-terminal deletion, substitution, and insertion mutants of TFIIIA in bacteria as fusions with maltose-binding protein (MBP). The MBP-TFIIIA fusion protein specifically binds to the 5S RNA gene internal control region and complements transcription in a TFIIIA-depleted oocyte nuclear extract. Random, cassette-mediated mutagenesis of the carboxyl region of TFIIIA, which is not required for promoter binding, has defined a 14-amino-acid region that is critical for transcriptional activation. In contrast to activators of RNA polymerase II, the activity of the TFIIIA activation domain is strikingly sensitive to its position relative to the DNA-binding domain. When the eight amino acids that separate the transcription-activating domain from the last zinc finger are deleted, transcriptional activity is lost. Surprisingly, diverse amino acids can replace these eight amino acids with restoration of full transcriptional activity, suggesting that the length and not the sequence of this region is important. Insertion of amino acids between the zinc finger region and the transcription-activating domain causes a reduction in transcription proportional to the number of amino acids introduced. We propose that to function, the transcription-activating domain of TFIIIA must be correctly positioned at a minimum distance from the DNA-binding domain.

N-(phosphonacetyl)-L-aspartate synergistically enhances the cytotoxicity of 5-fluorouracil/interferon-alpha-2a against human colon cancer cell lines

Recombinant interferon-alpha (IFN) enhances the cytotoxic effects of the fluorinated pyrimidine, 5-fluorouracil (5FU), against two human colon cancer cell lines. The aspartate transcarbamylase (ATCase) inhibitor, N-(phosphonacetyl)-L-aspartate (PALA), was studied in combination with 5FU/IFN to determine whether further anti-pyrimidine effects would result in greater cytotoxicity. By median effects analysis PALA synergistically augmented the cytotoxic effects of 5FU/IFN against both human colon cancer cell lines. This occurred in the absence of any effects of 5FU/IFN on ATCase and without further potentiation of the PALA-mediated inhibition of ATCase. To explore the mechanism by which this interaction occurred, detailed studies of pools of dNTPs were performed. Both 5FU/IFN and PALA/5FU/IFN treatments resulted in early (2-8 hr) depletion of pools of dTTP, but no effects on pools of dCTP. PALA had no effect on dTTP pools either alone or in the combination. In contrast, both PALA and PALA/5FU/IFN treatments resulted in later (12-24 hr) depletion of pools of dCTP. 5FU/IFN treatment had no effect on these pools. When pools of dCTP and dTTP were repleted by treatment with cytidine or thymidine, 20 microM, however, there was only partial reversal of cytotoxicity induced by 5FU/IFN + PALA, suggesting that the synergy observed did not result solely from a sequential anti-pyrimidine effect. The incorporation of 5FU into RNA was also studied; PALA enhanced the incorporation of [6-3H]5FU into RNA by 83-150%, but not into DNA, suggesting an alternative mechanism of drug interaction.

bcl-x, a bcl-2-related gene that functions as a dominant regulator of apoptotic cell death

We report the isolation of bcl-x, a bcl-2-related gene that can function as a bcl-2-independent regulator of programmed cell death (apoptosis). Alternative splicing results in two distinct bcl-x mRNAs. The protein product of the larger mRNA, bcl-xL, is similar in size and predicted structure to Bcl-2. When stably transfected into an IL-3-dependent cell line, bcl-xL inhibits cell death upon growth factor withdrawal at least as well as bcl-2. Surprisingly, the second mRNA species, bcl-xS, encodes a protein that inhibits the ability of bcl-2 to enhance the survival of growth factor-deprived cells. In vivo, bcl-xS mRNA is expressed at high levels in cells that undergo a high rate of turnover, such as developing lymphocytes. In contrast, bcl-xL is found in tissues containing long-lived postmitotic cells, such as adult brain. Together these data suggest that bcl-x plays an important role in both positive and negative regulation of programmed cell death.

Antigenic and molecular properties of Murayama virus isolated from cynomolgus monkeys: the virus is closely related to avian paramyxovirus type 2

A new virus that belonged to a member of paramyxovirus was isolated from cynomolgus monkeys showing respiratory disorders about 20 years ago and was named Murayama virus (MrV). Interestingly, it showed no serological relationship with the mammalian paramyxoviruses tested. On the other hand, it was related to Yucaipa (YuV) and Bangor virus (BaV) belonging to avian paramyxovirus type 2 (PMV2). In analysis using anti-MrV monoclonal antibodies, MrV showed the closest relationship with YuV, and furthermore some conserved epitopes were found among avian paramyxovirus, MrV, YuV, BaV, and Newcastle disease virus (NDV). Subsequently, the nucleotide sequences of the F and HN genes of MrV were determined. In comparison with the deduced amino acid sequence of MrV and other paramyxoviruses, MrV showed the highest homology with NDV and higher similarity to HPIV2 group rather than to HPIV1 group. The present study clearly indicates that MrV belongs to PMV2 adapting to monkeys.

The NFAT-1 DNA binding complex in activated T cells contains Fra-1 and JunB

Activation of T cells induces transcription of the interleukin-2 (IL-2) gene. IL-2 expression is regulated through the binding of transcription factors to multiple sites within the IL-2 enhancer. One such cis-acting element within the IL-2 enhancer is the NFAT-1 (nuclear factor of activated T cells) binding site. NFAT-1 binding activity is absent in resting cells but is induced upon T-cell activation. The induction of NFAT-1 binding activity can be inhibited by cyclosporin A, potentially accounting for the ability of cyclosporin A to inhibit IL-2 production by T cells. We have previously reported that the NFAT-1 binding complex is composed of at least two proteins and that the 5' portion of the NFAT-1 sequence acts as a binding site for one or more proteins from the Ets family of transcription factors. We now report that the 3' portion of the NFAT-1 sequence contains a variant AP-1 binding site. NFAT-1 binding can be specifically inhibited by oligonucleotides containing a consensus AP-1 site. Moreover, mutation of the AP-1 site at the 3' end of the NFAT-1 sequence inhibits both NFAT-1 binding and the ability of the NFAT-1 binding site to activate expression from a reporter plasmid upon T-cell activation. Since AP-1 sites bind dimeric protein complexes composed of individual members of the Fos and Jun families of transcription factors, we used antibodies specific for individual Fos and Jun family members to determine whether they are present in the NFAT-1 binding complex. These experiments demonstrated that the NFAT-1 binding complex contains JunB and Fra-1 proteins. Northern (RNA) blot analyses demonstrate that both fra-1 and junB mRNAs are induced upon T-cell activation, although fra-1 mRNA is present even in quiescent T cells. Of interest, junB is not expressed in quiescent T cells, and it is induced with kinetics that are similar to those for the induction of IL-2 mRNA expression. Taken together, these results suggested that the JunB-Fra-1 heterodimer is the inducible nuclear component of the NFAT-1 binding activity and that JunB expression regulates the formation of the heterodimer. In addition, these data indicated that specific heterodimers of Fos and Jun family members may have selective roles in the induction of transcription during cellular activation.

Regulation of translation initiation factor gene expression during human T cell activation

Activation of quiescent T cells leads to a dramatic increase in the rate of protein synthesis. It is believed that this pronounced increase of protein synthesis is regulated primarily at the level of translational initiation. Although considerable evidence demonstrates that translational initiation can be regulated at the post-translational level by the phosphorylation/dephosphorylation of translation initiation factors (eIFs) such as eIF-4E and eIF-2 alpha, additional mechanisms of eIF gene expression may also play a role in the regulation of translation in quiescent cells and/or during their subsequent induction to enter the cell cycle. To address this issue, gene expression of eIF-2 alpha, -4E, and -4A was studied in quiescent human peripheral blood T cells following stimulation through the T cell receptor-CD3 complex. Quiescent T cells expressed low levels of eIF-2 alpha, -4E, and -4A mRNAs and proteins as compared to proliferating T cells. Activation of resting T cells resulted in a rapid increase (20-50-fold) in the levels of these three mRNAs. This increase did not require new protein synthesis. Furthermore, transcription rates of these three eIF genes showed only minor increase over the induction period as measured by nuclear run-on assays. Despite the rapid increase in initiation factor mRNA levels, increases in eIF protein levels lagged significantly behind. Western blot analysis also showed that the protein levels of the three eIFs were differentially increased. eIF-4A protein levels increased in proportion to the observed increase in cellular protein synthetic activity while the increases in eIF-4E and eIF-2 alpha proteins were proportionately less. The low levels of eIF proteins in quiescent T cells appear to correlate with low protein synthesis rate in such cells. The induction of eIF proteins by post-transcriptional/translational mechanisms appears to contribute to the pronounced stimulation of protein synthesis that occurs during T cell activation.

[Study on relationship between human ABO blood groups and type A behavior pattern]

Investigation of the relationship between ABO blood groups (ABO BG) and Type A behavior pattern (TABP) was performed. No significant correlation was found between human ABO BG and TABP (P less than 0.05). However, CH and TH + CH scores in individuals with blood type A and type A personality were significantly lower (P less than 0.05). The values of TH-CH scores among tested people were of no statistical significance (P greater than 0.05). Moreover, nearly half of the examinees (41.32%) had higher CH score and the distribution of the individuals was obviously different in statistics (P less than 0.005). In addition, L score of examinees with blood type A and type B personality was relatively lower.