Expression of a ligninase by a new hybrid baculovirus with expanded host range

We have generated and purified a new recombinant baculovirus with expanded host range. AcNPV DNA and BamHI-digested BmNPV DNA were co-transfected into Spodoptera frugiperda SF21 cells. Progeny viruses were used to infect BmN cells, which are normally resistant to AcNPV infection, in other to screen for recombinant viruses with cross-infectivity. A recombinant virus was isolated by plaque purification and analyzed. This isolate was able to infect, replicate and produce polyhedrin in both the SF21 and BmN cells. DNA restriction endonuclease analysis showed that it was a hybrid (HyNPV) of AcNPV and BmNPV. Co-transfection of this HyNPV virus with a transfer vector containing a ligninase Hs gene insert into SF21 cells yielded a recombinant baculovirus expressing the ligninase. When this recombinant baculovirus was used to infect either SF21 or BmN cells, ligninase proteins could be found in the lysed cells as well as in the cell culture media. We have thus demonstrated that this hybrid virus can be utilized in the generation of recombinant baculovirus expressing foreign proteins in two host cells which normally can not be infected by AcNPV nor BmNPV

Evaluation of spent medium recycle and nutrient feeding strategies for recombinant protein production in the insect cell-baculovirus process

In the production of recombinant proteins by the insect cell-baculovirus process, fresh medium renewal prior to virus infection has been an effective measure for maintaining high protein yields. The spent medium used in the growth stage may still be unexhausted and can be reused for cell growth. In this study, we exercised the recycle of a spent insect cell medium for cell growth and recombinant protein production. It was found that the spent medium collected from a culture close to the stationary growth phase could provide full support for insect cell growth through another batch culture after fortified with suitable nutrients (yeastolate, glucose and glutamine) and a small fraction (15-20\%) of fresh medium. The specific and volumetric protein yields with cells grown in the recycled spent medium were in most cases similar to those with cells grown in fresh medium. Protein yields on per unit volume of fresh medium in the process incorporating spent medium recycle compared favourably with that achieved in a batch or fed-batch process. Spent medium recycle is hence a feasible alternative for the insect cell culture-baculovirus process. (C) 1998 Elsevier Science B.V. All rights reserved

Estrogen treatment induces elevated expression of HMG1 in MCF-7 cells

The high mobility group (HMG)1 protein is a highly conserved and ubiquitous chromosomal protein found enriched in active chromatin, In this study, we have investigated the effect of estrogen on the expression of the human high mobility group protein HMG1 gene and found that the HMG1 mRNA level in MCF-7 cells was sharply increased 2.5-fold after 30 min of estrogen treatment. Under continuous estrogen treatment, the HMG1 mRNA level decreased to a 1.5 times that of the basal level at 90 min and remained at this elevated level under estrogen treatment for up to 24 h. These results support the recent finding by Verrier et al, (C. S. Verrier, 1997, Mel. Endocrinol, 11, 1009-1019) that HMG1 promotes the binding of the estrogen receptor to the estrogen response element and further reinforce our believe that HMG1 plays a significant role in estrogen-induced gene expression. (C) 1998 Academic Press

Diastereoselective oxidation of 2,3-epoxy alcohol-derived thiiranes, and H-1 NMR analysis of the corresponding thiirane S-oxides

Anti-thiirane S-oxides derived from cis-2,3-epoxyhexan-1-ol are prepared to serve as transition state analogs for alkene epoxidation and singlet oxygenation. The P-hydroxyl directing effect commonly exploited in sulfide oxidations is found to be completely ineffective in directing oxidation of cis-epoxy alcohol-derived thiiranes; steric factors alone appear to determine the anti:syn selectivity. Detailed H-1 NMR analysis was performed on both the stable anti- and the unstable syn-thiirane S-oxides. The thiirane S-oxide ring protons are found to possess unusually large vicinal coupling constants (approx. 11 Hz) and their chemical shifts are quite sensitive to the anisotropy of the SO moiety

THE GENE FOR THE HUMAN ARCHITECTURAL TRANSCRIPTION FACTOR HMGI-C CONSISTS OF 5 EXONS EACH CODING FOR A DISTINCT FUNCTIONAL ELEMENT

The gene on chromosome 12 coding for the human protein HMGI-C has been cloned and partially sequenced, It consists of five exons, the first and last of which include long untranslated regions, The 5' UTR includes a (CA/T)(n) tract and a polymorphic (CT)(n) tract, Exons II, III and IV (87, 51 and 33 bp) are dispersed over >30 kb, Exons I-III separately encode the three basic DNA binding domains ('A-T hooks'), exon IV encodes an 11 amino acid sequence characteristic of HMGI-C and absent from the human HMGI(Y) gene [Friedmann,M., Holth, L.T., Zoghbi,H,Y, and Reeves,R, (1993) Nucleic Acids Res., 21, 4259-4267], whilst exon V encodes the acidic C-terminal domain, which is subject to multiple phosphorylation, The HMGI-C gene is thus a striking example of the separation of functional protein elements into different coding exons