scholarly journals Expression Systems and Species Used for Transgenic Animal Bioreactors

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Yanli Wang ◽  
Sihai Zhao ◽  
Liang Bai ◽  
Jianglin Fan ◽  
Enqi Liu
Keyword(s):  
Recombinant Proteins ◽  
Mammalian Cells ◽  
Mammalian Species ◽  
Therapeutic Proteins ◽  
Transgenic Animals ◽  
Mammary Glands ◽  
Transgenic Animal ◽  
High Fertility ◽  
Expression Systems ◽  
Specific Expression

Transgenic animal bioreactors can produce therapeutic proteins with high value for pharmaceutical use. In this paper, we compared different systems capable of producing therapeutic proteins (bacteria, mammalian cells, transgenic plants, and transgenic animals) and found that transgenic animals were potentially ideal bioreactors for the synthesis of pharmaceutical protein complexes. Compared with other transgenic animal expression systems (egg white, blood, urine, seminal plasma, and silkworm cocoon), the mammary glands of transgenic animals have enormous potential. Compared with other mammalian species (pig, goat, sheep, and cow) that are currently being studied as bioreactors, rabbits offer many advantages: high fertility, easy generation of transgenic founders and offspring, insensitivity to prion diseases, relatively high milk production, and no transmission of severe diseases to humans. Noticeably, for a small- or medium-sized facility, the rabbit system is ideal to produce up to 50 kg of protein per year, considering both economical and hygienic aspects; rabbits are attractive candidates for the mammary-gland-specific expression of recombinant proteins. We also reviewed recombinant proteins that have been produced by targeted expression in the mammary glands of rabbits and discussed the limitations of transgenic animal bioreactors.

Pharmaceutical and Biotechnological Applications of Transgenic Technology

2018 ◽  
Vol 11 (4) ◽  
pp. 4145-4153
Author(s):  
D Samba Reddy ◽  
Tina Reddy
Keyword(s):  
Mammalian Species ◽  
Genetic Diseases ◽  
Transgenic Animals ◽  
Transgenic Animal ◽  
Pharmaceutical Products ◽  
Conditional Knockout ◽  
Knock Out ◽  
Transgenic Lines ◽  
Health And Disease ◽  
Or Genes

A transgenic animal is a genetically modified species in which researchers have modified an existing gene or genes by genetic engineering techniques. Genetic modification involves the mutation, insertion, or deletion of genes. Mouse is the most widely used mammalian species for creating transgenic lines. There are two types of transgenic animals: (i) gene deleted (“knock-out”) and (ii) gene overexpressed (“knock-in”). The loss or gain of gene activity often causes changes in a mouse's phenotype, which includes appearance, behavior and other observable characteristics. Knockout mice are key animal models for studying the role of genes which have been sequenced but whose functions have not been determined.  They include constitutive knockouts (gene deleted since birth) and conditional knockout (gene turned off later after birth).  The first knockout mouse was created in 1989 by Mario Capecchi, Martin Evans, and Oliver Smithies, for which they were awarded the 2007 Nobel Prize in Physiology or Medicine.  Transgenic mouse models have revolutionized the biomedical research and provided a power tool for understanding health and disease. Transgenic animals have been created for bulk production of biotechnology and pharmaceutical products.  In 2009, the FDA approved the first human biological drug ATryn, an anticoagulant extracted from the transgenic goat's milk. The recently discovered CRISPER gene editing technology is providing new frontiers in correcting abnormal genes and hopefully provide cures for genetic diseases in the future.    

Multiple mRNAs encode the avian lysosomal membrane protein LAMP-2, resulting in alternative transmembrane and cytoplasmic domains

1995 ◽  
Vol 108 (5) ◽  
pp. 2093-2100 ◽  
Author(s):  
C.L. Hatem ◽  
N.R. Gough ◽  
D.M. Fambrough
Keyword(s):  
Alternative Splicing ◽  
Mammalian Cells ◽  
Splice Variants ◽  
Single Gene ◽  
Mammalian Species ◽  
Cdna Clones ◽  
Cytoplasmic Domains ◽  
Specific Expression ◽  
Adult Chicken ◽  
The Common

Lysosomal membranes are enriched in extensively glycosylated transmembrane proteins, LAMP-1 and LAMP-2. LAMP-1 proteins have been characterized from several mammalian species and from chickens, but no non-mammalian homologues of LAMP-2 have been described, and no splice variants of either protein have been reported. Here we report the characterization of three cDNA clones encoding chicken LAMP-2. The nucleotide sequences of the cDNAs diverge at their 3′ ends within the open reading frame, resulting in sequences that code for three different transmembrane and cytoplasmic domains. Southern analysis suggests that a single gene encodes the common region of chicken LAMP-2. The position of the divergence and the identity of the common sequence are consistent with alternative splicing of 3′ exons. Analysis of the mRNAs present in adult chicken tissues suggests tissue-specific expression of the three chicken LAMP-2 variants, with LAMP-2b expressed primarily in the brain. The cytoplasmic domain of LAMP-type proteins contains the targeting signal for directing these molecules to the lysosome. Using chimeras consisting of the lumenal domain of chicken LEP100 (a LAMP-1) and the transmembrane and cytoplasmic domains of the LAMP-2 variants, we demonstrate in transfected mouse L cells that all three LAMP-2 carboxyl-terminal regions are capable of targeting the chimeric proteins to lysosomes. Levels of expression, subcellular distribution, and glycosylation of the LAMP proteins have all been shown to change with differentiation in mammalian cells and to be correlated with metastatic potential in certain tumor cell lines. Alternative splicing of the LAMP-2 transcript may play a role in these changes.

scholarly journals Stable recombinant gene expression from a Ligilactobacillus live bacterial vector via chromosomal integration

2021 ◽  
Author(s):  
Ben Vezina ◽  
Theo Allnutt ◽  
Anthony L. Keyburn ◽  
Ben Wade ◽  
Thi Thu Hao Van ◽  
...  
Keyword(s):  
Gastrointestinal Tract ◽  
Protein Expression ◽  
Clostridium Perfringens ◽  
Recombinant Proteins ◽  
Therapeutic Proteins ◽  
Alternative Methods ◽  
Future Application ◽  
Expression Systems ◽  
Recombinant Gene Expression ◽  
Vaccine Antigens

Disease control in animal production systems requires constant vigilance. Historically, the application of in-feed antibiotics to control bacteria and improve performance has been a much-used approach to maintain animal health and welfare. However, the widespread use of in-feed antibiotics is thought to increase the risk of antibiotic resistance developing. Alternative methods to control disease and maintain productivity need to be developed. Live vaccination is useful in preventing colonisation of mucosal-dwelling pathogens by inducing a mucosal immune response. Native poultry isolate Ligilactobacillus agilis La3 (previously Lactobacillus agilis) has been identified as a candidate for use as a live vector to deliver therapeutic proteins such as bacteriocins, phage endolysins, or vaccine antigens to the gastrointestinal tract of chickens. In this study, the complete genome sequence of L. agilis La3 was determined and transcriptome analysis was undertaken to identify highly expressed genes. Predicted promoter regions and ribosomal binding sites from constitutively expressed genes were used to construct recombinant protein expression cassettes. A series of double-crossover shuttle plasmids were constructed, to facilitate rapid selectable integration of expression cassettes into the L. agilis La3 chromosome via homologous recombination. Inserts showed 100% stable integration over 100 generations without selection. A positive relationship was found between protein expression levels and the predicted strength of the promoters. Using this system, stable chromosomal expression of a Clostridium perfringens antigen, rNetB, was demonstrated without selection. Finally, two recombinant strains, L. agilis La3::Peft-rnetB and L. agilis La3::Pcwah-rnetB, were constructed, characterised, and showed potential for future application as live vaccines in chickens. Importance Therapeutic proteins such as antigens can be used to prevent infectious diseases in poultry. However, traditional vaccine delivery by intramuscular or subcutaneous injection has generally not proven effective for mucosal-dwelling microorganisms that live within the gastrointestinal tract. Utilising live bacteria to deliver vaccine antigens directly to the gut immune system can overcome some of the limitations of conventional vaccination. In this work, Ligilactobacillus agilis La3, an especially effective gut coloniser has been analysed and engineered with modular and stable expression systems to produce recombinant proteins. To demonstrate the effectiveness of the system, expression of a vaccine antigen from poultry pathogen Clostridium perfringens was monitored over 100 generations without selection and found to be completely stable. This study demonstrates the development of genetic tools, novel constitutive expression systems and further development of L. agilis La3 as a live delivery vehicle for recombinant proteins.

Comparison of the trans-activation capabilities of the human T-cell leukemia virus type I and II chi proteins

1986 ◽  
Vol 6 (11) ◽  
pp. 3626-3631
Author(s):  
N P Shah ◽  
W Wachsman ◽  
A J Cann ◽  
L Souza ◽  
D J Slamon ◽  
...  
Keyword(s):  
T Cell ◽  
Mammalian Cells ◽  
Leukemia Virus ◽  
Mammalian Species ◽  
Cellular Transformation ◽  
Type I ◽  
T Cell Leukemia ◽  
Cell Leukemia ◽  
Cell Leukemia Virus Type ◽  
Human T Cell

The mechanism of cellular transformation by the human T-cell leukemia viruses (HTLVs) is thought to involve a novel retrovirus gene known as chi. The chi gene is essential for HTLV replication and acts by enhancing transcription from the viral long terminal repeat. By using the HTLV type I and II chi gene-coding regions inserted into a highly efficient expression vector, we directly compared the efficiencies of the two chi proteins to trans activate the HTLV type I and II long terminal repeats. We demonstrate that the two chi proteins have different patterns of trans activation. The patterns were highly reproducible in all mammalian cells tested. A different pattern of activation was observed in avian cells. These results suggest that the mechanism of trans activation involves specific cellular factors that are highly conserved throughout mammalian species but different in avian cells. Understanding the mechanism of trans activation by the chi gene product may provide insights into mechanisms of cellular transformation by HTLV.

scholarly journals The role of biotechnology in the field of biomedical engineering

2021 ◽  
Vol 16 (2) ◽  
pp. 130-150
Author(s):  
Meheta Datta ◽  
Farzana A Khan ◽  
Sangjukta Das ◽  
Shreyosee Saha ◽  
Ruhul A Khan
Keyword(s):  
Insect Cells ◽  
Transgenic Animals ◽  
Expression Systems ◽  
Knowledge Domain ◽  
Modern Age ◽  
Engineering And Technology ◽  
Identical Nucleotide ◽  
Identical Nucleotide Sequence ◽  
Day By Day

The modern age is an arena of interdisciplinary research and knowledge domain which involves versatile field of sciences to work cooperatively for the improvement of the mankind. Biotechnology is providing for more personalized healthcare and continued analysis of the human body. As biotechnology advances day by day, we have to uphold the pace to discover future medical applications of it. Biotechnology is a huge and rapidly growing field. Biomedical technology involves the application of engineering and technology principles to the domain of living or biological systems. Generally biomedical denotes larger stress on issues related to human health and diseases. Different kinds of live expression systems like plant or insect cells, transgenic animals, mammals, yeast, Escherichia coli and more are particularly beneficial because biotechnology-derived medicines from them. This type of expressed gene or protein incorporates the identical nucleotide sequence as endogenous form of humans. Application of biotechnology in different domain of biomedical fields has already brought about a substantial difference which denotes the superiority over traditional ways of treatment. It is very easy to understand that how biotechnology can be played a crucial role in medical purposes. This paper will try to highlight the glimpse of multifaceted application of biotechnology in different field as well as from different angle of application.

scholarly journals Unconventional Translation Initiation Factor EIF2A is required for Drosophila spermatogenesis

2021 ◽  
Author(s):  
David D Lowe ◽  
Denise Montell
Keyword(s):  
Mammalian Cells ◽  
Translation Initiation Factor ◽  
Initiation Factor ◽  
Male Sterile ◽  
Specific Expression ◽  
Transposon Insertion ◽  
Stress Related Genes ◽  
Male Specific ◽  
Multicellular Organisms

The eukaryotic initiation factor EIF2A is an unconventional translation factor required for initiation of protein synthesis from non-AUG codons from a variety of transcripts, including oncogenes and stress related genes in mammalian cells. Its function in multicellular organisms has not been reported. Here, we identify and characterize mutant alleles of the CG7414 gene, which encodes the Drosophila EIF2A ortholog. We identified that CG7414 undergoes sex-specific splicing that regulates its male-specific expression. We characterized a Mi{Mic} transposon insertion that disrupts the coding regions of all predicted isoforms and is a genetic null allele, and a PBac transposon insertion into an intron, which is a hypomorph. The Mi{Mic} allele is homozygous lethal, while the viable progeny from the hypomorphic PiggyBac allele are male sterile and female fertile. In dEIF2A mutant flies, sperm failed to individualize due to defects in F-actin cones and failure to form and maintain cystic bulges, ultimately leading to sterility. These results demonstrate that EIF2A is essential in a multicellular organism, both for normal development and spermatogenesis, and provide an entree into the elucidation of the role of EIF2A and unconventional translation in vivo.

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