Transgene inactivation inPetunia hybrida is influenced by the properties of the foreign gene

1995 ◽  
Vol 248 (6) ◽  
pp. 649-656 ◽  
Author(s):  
Paula Elomaa ◽  
Yrjö Helariutta ◽  
Mika Kotilainen ◽  
Teemu H. Teeri ◽  
Robert J. Griesbach ◽  
...  
1993 ◽  
Vol 76 (11) ◽  
pp. 3392-3399 ◽  
Author(s):  
Esmail Behboodi ◽  
G.B. Anderson ◽  
S. Horvat ◽  
J.F. Medrano ◽  
J.D. Murray ◽  
...  

2021 ◽  
Vol 9 (5) ◽  
pp. 1005
Author(s):  
Olga Chervyakova ◽  
Elmira Tailakova ◽  
Nurlan Kozhabergenov ◽  
Sandugash Sadikaliyeva ◽  
Kulyaisan Sultankulova ◽  
...  

Capripoxviruses with a host range limited to ruminants have the great potential to be used as vaccine vectors. The aim of this work was to evaluate attenuated sheep pox virus (SPPV) vaccine strain NISKHI as a vector expressing several genes. Open reading frames SPPV020 (ribonucleotide kinase) and SPPV066 (thymidine kinase) were selected as sites for the insertion of foreign genes. Two integration plasmids with expression cassette were designed and constructed. Recombinant SPPVs expressing an enhanced green fluorescent protein (EGFP) (rSPPV(RRΔ)EGFP and rSPPV(TKΔ)EGFP), Foot-and-mouth disease virus capsid protein (VP1), and Brucella spp. outer membrane protein 25 (OMP25) (rSPPV(RRΔ)VP1A-(TKΔ)OMP25) were generated under the transient dominant selection method. The insertion of foreign genes into the SPPV020 and SPPV066 open reading frames did not influence the replication of the recombinant viruses in the cells. Successful foreign gene expression in vitro was assessed by luminescent microscopy (EGFP) and Western blot (VP1 and OMP25). Our results have shown that foreign genes were expressed by rSPPV both in permissive (lamb testicles) and non-permissive (bovine kidney, saiga kidney, porcine kidney) cells. Mice immunized with rSPPV(RRΔ)VP1A-(TKΔ)OMP25 elicited specific antibodies to both SPPV and foreign genes VP1 and OMP25. Thus, SPPV NISKHI may be used as a potential safe immunogenic viral vector for the development of polyvalent vaccines.


1995 ◽  
Vol 73 (S1) ◽  
pp. 891-897 ◽  
Author(s):  
James M. Cregg ◽  
David R. Higgins

The methanol-utilizing yeast Pichia pastoris has been developed as a host system for the production of heterologous proteins of commercial interest. An industrial yeast selected for efficient growth on methanol for biomass generation, P. pastoris is readily grown on defined medium in continuous culture at high volume and density. A unique feature of the expression system is the promoter employed to drive heterologous gene expression, which is derived from the methanol-regulated alcohol oxidase I gene (AOX1) of P. pastoris, one of the most efficient and tightly regulated promoters known. The strength of the AOX1 promoter results in high expression levels in strains harboring only a single integrated copy of a foreign-gene expression cassette. Levels may often be further enhanced through the integration of multiple cassette copies into the P. pastoris genome and strategies to construct and select multicopy cassette strains have been devised. The system is particularly attractive for the secretion of foreign-gene products. Because P. pastoris endogenous protein secretion levels are low, foreign secreted proteins often appear to be virtually the only proteins in the culture broth, a major advantage in processing and purification. Key words: heterologous gene expression, methylotrophic yeast, Pichia pastoris, secretion, glycosylation.


2005 ◽  
Vol 79 (20) ◽  
pp. 12742-12751 ◽  
Author(s):  
Cornelis A. M. de Haan ◽  
Bert Jan Haijema ◽  
David Boss ◽  
Frank W. H. Heuts ◽  
Peter J. M. Rottier

ABSTRACT Coronaviruses are enveloped, positive-stranded RNA viruses considered to be promising vectors for vaccine development, as (i) genes can be deleted, resulting in attenuated viruses; (ii) their tropism can be modified by manipulation of their spike protein; and (iii) heterologous genes can be expressed by simply inserting them with appropriate coronaviral transcription signals into the genome. For any live vector, genetic stability is an essential requirement. However, little is known about the genetic stability of recombinant coronaviruses expressing foreign genes. In this study, the Renilla and the firefly luciferase genes were systematically analyzed for their stability after insertion at various genomic positions in the group 1 coronavirus feline infectious peritonitis virus and in the group 2 coronavirus mouse hepatitis virus. It appeared that the two genes exhibit intrinsic differences, the Renilla gene consistently being maintained more stably than the firefly gene. This difference was not caused by genome size restrictions, by different effects of the encoded proteins, or by different consequences of the synthesis of the additional subgenomic mRNAs. The loss of expression of the firefly luciferase was found to result from various, often large deletions of the gene, probably due to RNA recombination. The extent of this process appeared to depend strongly on the coronaviral genomic background, the luciferase gene being much more stable in the feline than in the mouse coronavirus genome. It also depended significantly on the particular genomic location at which the gene was inserted. The data indicate that foreign sequences are more stably maintained when replacing nonessential coronaviral genes.


2021 ◽  
Vol 1 (7) ◽  
pp. 44-50
Author(s):  
N. A. Popov ◽  

The aspects of reasonableness in developing the line breeding strategy at the current status stage of dairy breeds and its significance as a factor for genetic variability have been reported. The value for milk production of the first-calf heifers within the line-bred pedigree Red-and-White cattle is estimated. Particular characteristics of the progeny produced from mating in the inbred and crossbred lines are recorded. The lower trait variability of traits was found with selecting within the crossbred lines than that in the inbred lines. Thus, the variables for the milk yield, the mass fraction of fat (MFF) in milk, and the mass fraction of protein (MFP) were less by 4–13% of the mean square deviation, 11,3–20,6%, and 14,3%, respectively. Livestock breed differentiation between the breeding lines was previously executed with the artificial elements of isolation systems. At present, the breeds widely distributed in the Russian Federation are usually “improved” with the use of Holsteins. Therefore, their genealogy and breeding structures depend on the foreign gene pool. Selection strategies for the improvement of milkability traits were implemented along with selection of bull sires capable of improving the conformation. In addition, certain herd bulls were used repeatadly. The variables for genetic values for milkability traits, which changed over time, were monitored. The herd milk production within the lines over a generation increased by 624–786 kg milk (P<0,001), while the MFF deacresed by 0,18–0,25% (P<0,001). Depending on the types of breeding, the differences in the milk yields and the MFF of the first-calf heifers between the lines comprised 178–444 kg (P<0,001) and +0.01%, respectively. However, a statistically significant difference between the lines was recorded only for the MFP, which comprised 0,03% (P<0,001).


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