2',5'-Oligoadenylate synthetase (2-5OAS) is one of the interferon (IFN)-induced proteins and mediates the antiviral action of IFN. In human, three classes of 2-5OAS genes (OAS1, OAS2, and OAS3) and one OAS-like gene (OASL) are reported. In mice, however, OAS genes corresponding to human OAS2 and OAS3 have not been identified. In this report, we identified six novel OAS family genes in mice by screening mouse genomic library and expressed sequence tag (EST) database. These genes include three homologs of the human OAS1 and each homologous gene of the human OAS2, OAS3, and OASL, respectively. Each gene displays 52%-65% amino acid identity to the corresponding human homologs. Nine 2-5OAS genes, except for two OASL genes, locate within the 210-kb genomic region and form a cluster. Each novel 2-5OAS gene showed a characteristic expression pattern among different tissues, and all of them were induced by polyinosinic-polycytidylic acid. Biochemical analyses using recombinant proteins produced in Escherichia coli showed that all the novel mouse 2-5OAS molecules have double-stranded RNA (dsRNA) binding ability, but they do not have 2-5OAS activity except for the OAS2 and OAS3 mouse homologs. These results show that there are at least 11 OAS genes, which are classified into four groups, in the mouse.

Dendritic cell (DC)-based cancer immunotherapy has been paid much attention as a new and cancer cell-specific therapeutic in the last decade; however, little clinical outcome has been reported. Current limitations of DC-based cancer immunotherapy include sparse information about which DC phenotype should be administered. We here report a unique, representative, and powerful method to activate DCs, namely recombinant Sendai virus-modified DCs (SeV/DC), for cancer immunotherapy. In vitro treatment of SeV without any bioactive gene solely led DCs to a mature phenotype. Even though the expression of surface markers for DC activation ex vivo did not always reach the level attained by an optimized amount of LPS, superior antitumor effects to B16F1 melanoma, namely tumor elimination and survival, were obtained with use of SeV-GFP/DC as compared with those seen with LPS/DC in vivo, and the effect was enhanced by SeV/DC-expressing IFN-β (SeV-murine IFN-β (mIFN-β)/DC). In case of the treatment of an established tumor of B16F10 (7–9 mm in diameter), a highly malignant subline of B16 melanoma, SeV-modified DCs (both SeV-GFP/DC and SeV-mIFN-β/DC), but not immature DC and LPS/DC, dramatically improved the survival of animals. Furthermore, SeV-mIFN-β/DC but not other DCs could lead B16F10 tumor to the dormancy, associated with strongly enhanced CD8+ CTL responses. These results indicate that rSeV is a new and powerful tool as an immune booster for DC-based cancer immunotherapy that can be significantly modified by IFN-β, and SeV/DC, therefore, warrants further investigation as a promising alternative for cancer immunotherapy.

Recent inquiries have revealed a surprisingly large number (>2500) of naturally occurring antisense transcripts, but their function remains largely undiscovered. A better understanding of antisense mechanisms is clearly needed because of their potentially diverse roles in gene regulation and disease. A well-documented case occurs in X inactivation, the mechanism by which X-linked gene expression is equalized between XX females and XY males. The antisense gene Tsix determines X chromosome choice and represses the noncoding silencer, Xist. In principle, Tsix action may involve RNA, the act of transcription, or local chromatin. Here, we create novel Tsix alleles to distinguish transcription- versus RNA-based mechanisms. When Tsix transcription is terminated before Xist (TsixTRAP), Tsix cannot block Xist upregulation, suggesting the importance of overlapping antisense transcription. To separate the act of transcription from RNA, we knocked in Tsix cDNA in the reverse orientation (Tsix(cDNA)) to restore RNA levels in cis without concurrent transcription across Xist. However, Tsix(cDNA) cannot complement TsixTRAP. Surprisingly, both mutations disrupt choice, indicating that this epigenetic step requires transcription. We conclude that the processed antisense RNA does not act alone and that Tsix function specifically requires antiparallel transcription through Xist. A mechanism of transcription-based feedback regulation is proposed.