EMBRYO MANIPULATION AND GENE TRANSFER IN LIVESTOCK

1985 ◽  
Vol 65 (3) ◽  
pp. 527-538 ◽  
Author(s):  
R. B. CHURCH ◽  
F. J. SCHAUFELE ◽  
K. MECKLING
Keyword(s):  
Gene Transfer ◽  
Genetic Engineering ◽  
Embryo Transfer ◽  
Dna Sequences ◽  
Recombinant Dna ◽  
Fusion Gene ◽  
Bovine Genome ◽  
Monozygotic Twins ◽  
Genetically Engineered ◽  
Livestock Species

In the past few years significant progress has been made in manipulation of reproduction and in development of genetic engineering techniques which can be applied to animal species. Artificial insemination and embryo transfer are now used widely in the livestock industry. The advent of non-surgical embryo collection and transfer, embryo freezing and splitting along with estrus synchronization has allowed the industry to move from the laboratory to the farm. Embryo manipulation now involves embryo splitting to produce monozygotic twins, in vitro fertilization, cross-species fertilization, embryo sexing, and chimeric production of tetraparental animals among others. Advances in recombinant DNA, plasmid construction and embryo manipulation technologies allow the production of genetically engineered animals. The application of recombinant DNA technology involves the isolation and manipulation of desired genes which have potential for significant changes in productivity in genetically engineered livestock. Recombinant DNA constructs involve the coupling of promoter, enhancer, regulatory and structural DNA sequences to form a "fusion gene" which can then be multiplied, purified, assayed and expressed in cell culture prior to being introduced into an animal genome. Such DNA gene constructs are readily available for many human and mouse genes. However, they are not readily available for livestock species because the detailed molecular biology has not yet been established in these species. Gene transfer offers a powerful new tool in animal research. Transfer of genes into the bovine genome has been accomplished. However, successful directed expression of these incorporated genes has not been achieved to date. New combinations of fusion genes may be an effective way of producing transgenic domestic animals which show controlled expression of the desired genes. Embryo manipulation and genetic engineering in livestock species is moving rapidly. The problems being addressed at present in numerous laboratories will result in enhanced livestock production in the not too distant future. Key words: Embryo transfer, embryo manipulation, transgenic livestock, genetic engineering, gene transfer, monozygotic twins

Recombinant DNA Plasmid Transmission to Indigenous Organisms during Waste Treatment

1988 ◽  
Vol 20 (11-12) ◽  
pp. 179-184 ◽  
Author(s):  
M. A. Gealt
Keyword(s):  
Gene Transfer ◽  
Dna Sequences ◽  
Dna Hybridization ◽  
Waste Treatment ◽  
Recombinant Dna ◽  
Genetically Engineered ◽  
Environmental Damage ◽  
Bacterial Conjugation ◽  
Genetically Engineered Microorganisms ◽  
Dna Plasmid

The release of genetically engineered microorganisms into the environment will occur because of its importance to industrial and agricultural progress. Since organisms designed for release can be modified to survive only the time necessary for their function, the greatest potential for environmental damage depends upon the capability for mobilization of the genetically engineered DNA sequences (GEDS). Mobilization of GEDS to indigenous wastewater organisms by the process of bacterial conjugation has been demonstrated. This gene transfer, which will occur in a laboratory-scale waste treatment facility (~20 L capacity), depends on the presence of bacteria containing conjugative plasmids, many of which are indigenous to waste water. Sensitive detection of GEDS transfer requires the use of DNA-DNA hybridization. Environmental conditions do affect the frequency of conjugal gene transfer.

P–770 Two in One - Monozygotic splitting and associated perinatal outcomes after oocyte freezing; an exploratory analysis of the UK national database from 1990 to 2016

2021 ◽  
Vol 36 (Supplement_1) ◽  
Author(s):  
M Mascarenhas ◽  
P Mehlawat ◽  
M Choudhary
Keyword(s):  
Cohort Study ◽  
Genetic Testing ◽  
Embryo Transfer ◽  
Statistical Significance ◽  
Significant Risk ◽  
Monozygotic Twins ◽  
National Database ◽  
Assisted Hatching ◽  
Assisted Reproductive Technique ◽  
Oocyte Freezing

Abstract Study question Is oocyte freezing a risk factor for monozygotic splitting? Summary answer There is a trend towards a higher monozygotic splitting incidence among frozen oocytes, but this did not reach statistical significance. What is known already Laboratory techniques which involve embryo manipulation such as ICSI, assisted hatching, embryo biopsy for pre-implantation genetic testing and extended culture to the blastocyst stage appear to increase the risk of monozygotic splitting. Whilst there is some data that embryo freezing does not appear to increase the risk of monozygotic splitting, there is no comparable analysis on whether oocyte freezing increases the risk of monozygotic splitting. Study design, size, duration This was a retrospective cohort study analysing 988 015 ART (assisted reproductive technique) cycles from the HFEA anonymised database from 1990 to 2016. As frozen oocytes require ICSI, only fresh oocytes with ICSI were taken for comparison and frozen embryo transfers were excluded. Only single embryo transfers were included.[CM1] [MM2] We also noted ages of the female partner at the time of treatment, stage of embryo transfer, and whether pre-implantation genetic testing had been performed. Participants/materials, setting, methods There were 84 085 ICSI cycles with single embryo transfers using fresh oocytes and 596 using frozen oocytes. Monozygotic splitting was defined as the presence of two foetal hearts [CM1] [MM2] on ultrasound. Live birth (LB)was defined as either a singleton or a twin LB resulting from a monozygotically split embryo. Preterm birth (PTB) was defined as birth prior to 37 weeks gestation and early PTB as birth prior to 32 weeks gestation. Main results and the role of chance The frozen oocyte group had fewer women in the under–35 age group (frozen oocytes 16.6% vs fresh oocytes 53.6%, p < 0.0001) and a higher proportion of blastocyst transfers ( frozen oocytes 55.1% vs fresh oocytes 48.8%, p = 0.002) There were only 10 PGT cycles amongst monozygotically split embryos from fresh oocytes in our analysis, and none in the frozen oocyte group. Hence, this was not included as a confounder. There was a non-significant trend toward a higher incidence of monozygotic splitting amongst frozen oocytes (4/596, 2.3%, all monozygotic twins) than amongst fresh oocytes (378/27 019, 1.4%, 372 monozygotic twins and 6 monozygotic triplets); OR 1.688, 95% CI 0.623 to 4.574 and aOR 1.506, 95% CI 0.531 to 4.274 (maternal age and stage of embryo transfer adjusted as confounders). Of the 378 monozygotically split embryos from fresh oocytes, 308 (81.5%) had a LB: of which 47 (15.3%) were singletons and the rest were twins; 241 (78.2%) were PTB and 56 (18.2%) were early PTB. Of the four monozygotic twins from frozen oocytes, all reached a LB; one was a singleton term LB (Birthweight 3–3.5kg) whilst three were twin preterm LBs at 35–36 weeks, with no early PTBs and twin median birthweight 2–2.5 kg. Limitations, reasons for caution Albeit a large national database, this cohort study was restricted due to absence of data on potential confounders such as age at oocyte freezing, method of cryopreservation and length of storage.[CM1] Data was also lacking on amnionicity, obstetric risks including pre-eclampsia, twin-to-twin-transfusion syndrome, intrapartum and late effects. Wider implications of the findings: With rapid rise in egg freezing, our findings would help reassure women that eggs on ice does not predispose to significant risk of two-in-one monozygotic splitting. However, the marginal trend (from 1.4% in fresh to 2.3% in frozen oocytes), does indicate that this subject merits further research. Trial registration number Not applicable. A database based retrospective study

Complementation of a methotrexate uptake defect in Chinese hamster ovary cells by DNA-mediated gene transfer

1989 ◽  
Vol 9 (4) ◽  
pp. 1754-1758
Author(s):  
T M Underhill ◽  
W F Flintoff
Keyword(s):  
Gene Transfer ◽  
Dna Sequences ◽  
Chinese Hamster Ovary ◽  
Chinese Hamster Ovary Cells ◽  
Chinese Hamster ◽  
Ovary Cell ◽  
Wild Type ◽  
Ovary Cells ◽  
Ovary Cell Line ◽  
Human Specific

A methotrexate-resistant Chinese hamster ovary cell line deficient in methotrexate uptake has been complemented to methotrexate sensitivity by transfection with DNA isolated from either wild-type Chinese hamster ovary or human G2 cells. Primary and secondary transfectants regained the ability to take up methotrexate in a manner similar to that of wild-type cells, and in the case of those transfected with human DNA, to contain human-specific DNA sequences. The complementation by DNA-mediated gene transfer of this methotrexate-resistant phenotype provides a basis for the cloning of a gene involved in methotrexate uptake.

Genetically-Engineered Protease-Activated Triggers in a Pore-Forming Protein

1993 ◽  
Vol 330 ◽  
Author(s):  
Barbara Walker ◽  
Nathan Walsh ◽  
Hagan Bayley
Keyword(s):  
Genetic Engineering ◽  
Cancer Cells ◽  
Pore Formation ◽  
Polypeptide Chain ◽  
Genetically Engineered ◽  
Recognition Sequence ◽  
Selective Activation ◽  
Selective Destruction ◽  
Pore Forming Proteins ◽  
Central Loop

ABSTRACTProtease-activated triggers have been introduced Into a pore-forming protein, staphylococcal a-hemolysin (αHL). The hemolysin was remodeled by genetic engineering to form two-chain constructs with redundant polypeptide sequences at the central loop, the Integrity of which Is crucial for efficient pore formation. The new hemolysins are activated when the polypeptide extensions are removed by proteases. By alterating the protease recognition sequence in the loop, selective activation by specified proteases can be obtained. Protease-triggered pore-forming proteins might be used for the selective destruction of cancer cells that bear tumor-associated proteases. When certain two-chain constructs are treated with proteases, a full-length polypeptide chain forms as the result of a protease-mediated transpeptidation reaction. This reaction might be used to produce chimeric hemolysins that are Inaccessible by conventional routes.

scholarly journals Making of fusion genes in cancer: An in-silico study of mechanism of chromosomal translocations

2018 ◽  
Author(s):  
Kiran Lalwani ◽  
Shivani Sheth ◽  
Inayatullah Sheikh ◽  
Afzal Ansari ◽  
Fulesh Kunwar ◽  
...  
Keyword(s):  
Dna Sequences ◽  
In Silico ◽  
Molecular Mechanisms ◽  
Fusion Gene ◽  
Genetic Material ◽  
Chromosomal Translocations ◽  
In Silico Study ◽  
Clinical Consequences ◽  
The Stability ◽  
Genomic Regions

Chromosomal translocations involve exchange of genetic material between non- homologous chromosomes leading to the formation of a fusion gene with altered function. The clinical consequences of non-random and recurrent chromosomal translocations have been so well understood in carcinogenesis that they serve as diagnostic and prognostic markers and also help in therapy decisions, mainly in leukemia and lymphoma. However, the molecular mechanisms underlying these recurrent genetic exchanges are yet to be understood. Various approaches employed include the extent of the vicinity of the partner chromosomes in the nucleus, DNA sequences at the breakpoints, etc. The present study addresses the stability of DNA sequences at the breakpoint regions using in-silico approach in terms of physicochemical properties such as; AT%, flexibility, melting temperature, enthalpy, entropy, stacking energy and free energy. Changes in these properties may lead to instability of DNA which could affect gene expression in particular and genome organization in general. Our study indicates that the fusion sequences are comparatively more unstable and hence, more prone to breakage. Current study along with others could lead to developing a model for predicting breakage prone genomic regions using this novel in-silico approach.

scholarly journals Organization of lin Genes and IS6100 among Different Strains of Hexachlorocyclohexane-Degrading Sphingomonas paucimobilis: Evidence for Horizontal Gene Transfer

2004 ◽  
Vol 186 (8) ◽  
pp. 2225-2235 ◽  
Author(s):  
Charu Dogra ◽  
Vishakha Raina ◽  
Rinku Pal ◽  
Mrutyunjay Suar ◽  
Sukanya Lal ◽  
...  
Keyword(s):  
Gene Transfer ◽  
Horizontal Gene Transfer ◽  
Dna Sequences ◽  
Dna Hybridization ◽  
Gene Organization ◽  
Mycobacterium Fortuitum ◽  
Sphingomonas Paucimobilis ◽  
Hybridization Data ◽  
Different Strains ◽  
Geographical Locations

ABSTRACT The organization of lin genes and IS6100 was studied in three strains of Sphingomonas paucimobilis (B90A, Sp+, and UT26) which degraded hexachlorocyclohexane (HCH) isomers but which had been isolated at different geographical locations. DNA-DNA hybridization data revealed that most of the lin genes in these strains were associated with IS6100, an insertion sequence classified in the IS6 family and initially found in Mycobacterium fortuitum. Eleven, six, and five copies of IS6100 were detected in B90A, Sp+, and UT26, respectively. IS6100 elements in B90A were sequenced from five, one, and one regions of the genomes of B90A, Sp+, and UT26, respectively, and were found to be identical. DNA-DNA hybridization and DNA sequencing of cosmid clones also revealed that S. paucimobilis B90A contains three and two copies of linX and linA, respectively, compared to only one copy of these genes in strains Sp+ and UT26. Although the copy number and the sequence of the remaining genes of the HCH degradative pathway (linB, linC, linD, and linE) were nearly the same in all strains, there were striking differences in the organization of the linA genes as a result of replacement of portions of DNA sequences by IS6100, which gave them a strange mosaic configuration. Spontaneous deletion of linD and linE from B90A and of linA from Sp+ occurred and was associated either with deletion of a copy of IS6100 or changes in IS6100 profiles. The evidence gathered in this study, coupled with the observation that the G+C contents of the linA genes are lower than that of the remaining DNA sequence of S. paucimobilis, strongly suggests that all these strains acquired the linA gene through horizontal gene transfer mediated by IS6100. The association of IS6100 with the rest of the lin genes further suggests that IS6100 played a role in shaping the current lin gene organization.

Genetic engineering of virus resistance: a successful genetical alchemy

1992 ◽  
Vol 99 (3-4) ◽  
pp. 61-77
Author(s):  
B. D. Harrison
Keyword(s):  
Genetic Engineering ◽  
Resistance Genes ◽  
Virus Resistance ◽  
Crop Improvement ◽  
Genetically Engineered ◽  
Satellite Rna ◽  
Virus Diseases ◽  
Naturally Occurring ◽  
Resistance To Infection ◽  
Specific Tolerance

SynopsisSome of the most successful early applications of genetic engineering in crop improvement have been in the production of virus-resistant plants. This has been achieved not by the transfer of naturally occurring resistance genes from one plant species or variety to another but by transformation with novel resistance genes based on nucleotide sequences derived from the viruses themselves or from virus-associated nucleic acids. Transformation of plants with a DNA copy of the particle protein gene of viruses that have positive-sense single-stranded RNA genomes typically confers resistance to infection with the homologous and closely related viruses. Transformation with a gene that is transcribed to produce a benign viral satellite RNA can confer virus-specific tolerance of infection. In addition, recent work with viral poly-merase gene-related sequences offers much promise, and research is active on other strategies such as the use of virus-specific ribozymes.Already the field trialling of plants incorporating transgenic virus resistance has begun, with encouraging results, and effects on virus spread are being studied. Deployment strategies for the resistant plants must now be devised and the conjectural hazards of growing them assessed. Genetically engineered virus resistance promises to make a major contribution to the control of plant virus diseases by non-chemical methods.

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