scholarly journals Mathematical model of the multi-amino acid multi-transporter system predicts uptake flux in CHO cells

2021 ◽  
Author(s):  
Ashley Sreejan ◽  
Mugdha Gadgil ◽  
Chetan J. Gadgil
Keyword(s):  
Mathematical Model ◽  
Amino Acid ◽  
Cho Cells

scholarly journals A gene that is related to SRY and is expressed in the testes encodes a leucine zipper-containing protein.

1995 ◽  
Vol 15 (7) ◽  
pp. 3759-3766 ◽  
Author(s):  
N Takamatsu ◽  
H Kanda ◽  
I Tsuchiya ◽  
S Yamada ◽  
M Ito ◽  
...  
Keyword(s):  
Rainbow Trout ◽  
Amino Acid ◽  
Amino Acid Sequence ◽  
Cdna Library ◽  
Cho Cells ◽  
Leucine Zipper ◽  
Leucine Zipper Motif ◽  
Hmg Box ◽  
Testis Cdna Library ◽  
Testis Cdna

SRY-related cDNA encoding a protein with a high-mobility-group (HMG) box and a leucine zipper motif, which was designated SOX-LZ, was isolated from a rainbow trout testis cDNA library. Comparison of this cDNA with the mouse homologous cDNA isolated from a testis cDNA library exhibits an overall amino acid sequence identity of 77%, which is in striking contrast to the abrupt loss of amino acid sequence homology outside the HMG box found among mammalian SRY genes. In both rainbow trout and mice, Northern (RNA) blot analyses have revealed the presence of a testis-specific 3-kb-long SOX-LZ mRNA, and this transcript appeared coincidentally with the protamine mRNA, suggesting its expression in the germ line. A recombinant HMG box region protein encoded by SOX-LZ could bind strongly with an oligonucleotide containing an AACAAT sequence, which is also recognized by mouse Sry and Sox-5. Upon cotransfection into CHO cells, SOX-LZ transactivated transcription through its binding motif when the region including the leucine zipper motif was deleted [SOX-LZ (D105-356)]; however, the intact SOX-LZ failed to transactivate. The intact SOX-LZ could form homodimers through the leucine zipper, which resulted in inhibition of DNA binding by the HMG box, while SOX-LZ (D105-356), which was incapable of dimerization, showed specific binding with the AACAAT sequence. Thus, the repressed transactivation of the intact SOX-LZ in CHO cells was primarily attributable to the low level of DNA binding of SOX-LZ homodimers.

Six complementation classes of conditionally lethal protein synthesis mutants of CHO cells selected by3H-amino acid

1978 ◽  
Vol 4 (1) ◽  
pp. 27-44 ◽  
Author(s):  
Gerald M. Adair ◽  
Larry H. Thompson ◽  
Patricia A. Lindl
Keyword(s):  
Protein Synthesis ◽  
Amino Acid ◽  
Cho Cells

scholarly journals cDNA cloning and expression of a human platelet-derived growth factor (PDGF) receptor specific for B-chain-containing PDGF molecules.

1988 ◽  
Vol 8 (8) ◽  
pp. 3476-3486 ◽  
Author(s):  
L Claesson-Welsh ◽  
A Eriksson ◽  
A Morén ◽  
L Severinsson ◽  
B Ek ◽  
...  
Keyword(s):  
Amino Acid ◽  
Growth Factor ◽  
Cdna Cloning ◽  
Cho Cells ◽  
Chinese Hamster ◽  
Cloning And Expression ◽  
Platelet Derived Growth Factor ◽  
Amino Acid Sequence Similarity ◽  
Pdgf Receptor

The structure of the human receptor for platelet-derived growth factor (PDGF) has been deduced through cDNA cloning. A 5.45-kilobase-pair cDNA clone predicts a 1,106-amino-acid polypeptide, including the cleavable signal sequence. The overall amino acid sequence similarity with the murine PDGF receptor is 85%. After transcription of the cDNA and translation in vitro, a PDGF receptor antiserum was used to immunoprecipitate a product of predicted size, which also could be phosphorylated in vitro. Stable introduction of the cDNA into Chinese hamster ovary (CHO) cells led to the expression of a 190-kilodalton component, which was immunoprecipitated by the PDGF receptor antiserum; this most probably represents the mature PDGF receptor. Binding assays with different 125I-labeled dimeric forms of PDGF A and B chains showed that the PDGF receptor expressed in CHO cells bound PDGF-BB and, to a lesser extent, PDGF-AB, but not PDGF-AA.

scholarly journals Expression of the surface antigen 4F2hc affects system-L-like neutral-amino-acid-transport activity in mammalian cells

1997 ◽  
Vol 324 (2) ◽  
pp. 535-541 ◽  
Author(s):  
Stefan BRÖER ◽  
Angelika BRÖER ◽  
Bernd HAMPRECHT
Keyword(s):  
Amino Acid ◽  
Surface Antigen ◽  
Amino Acid Transport ◽  
Cho Cells ◽  
Mammalian Cells ◽  
Primary Cultures ◽  
Transport Systems ◽  
Acid Transport ◽  
Transport Activity ◽  
System L

Mammalian cells possess a variety of amino acid-transport systems with overlapping substrate specificity. System L is one of the major amino acid-transport systems of non-epithelial cells. By expression cloning we have recently demonstrated that the surface antigen 4F2hc (CD98) is a necessary component for expression of system-L-like amino acid-transport activity in C6-BU-1 rat glioma cells [Bröer, Bröer and Hamprecht (1995) Biochem. J. 312, 863–870]. 4F2hc mRNA was detected in CHO cells, COS cells, activated lymphocytes isolated from mouse spleen and primary cultures of astrocytes. In all these cell types, Na+-independent isoleucine transport was mediated by system L. No contribution of system y+L to isoleucine or arginine transport was detected in C6-BU-1 cells. In lymphocytes, both system-L-like amino acid-transport activity and 4F2hc mRNA levels increased after treatment with phorbol ester plus ionomycin. Antisense oligonucleotides caused modest inhibition of Na+-independent isoleucine transport in C6-BU-1 cells and primary cultures of astroglial cells, whereas arginine transport was unaffected. Overexpression of 4F2hc cDNA in CHO cells resulted in an increase in Na+-independent isoleucine transport.

scholarly journals Теоретичне обгрунтування співвідношення треоніну і триптофану у раціонах ремонтних курчат

2017 ◽  
Vol 7 (3) ◽  
pp. 111-115
Author(s):  
M.J. Krivenok ◽  
I.I. Ilchuk ◽  
V.M. Mykhalska
Keyword(s):  
Mathematical Model ◽  
Amino Acids ◽  
Amino Acid ◽  
Nonlinear Model ◽  
Linear Dependence ◽  
Growth And Development ◽  
Control Group ◽  
Growing Period ◽  
Different Content ◽  
Different Levels

<p>We determined the optimal content and ratio of threonine and tryptophan in the mix fodder of replacement chicks at different periods of their growing. We studied the effect of different levels of threonine and tryptophan in mixed fodder on chicken growth and development. We registered that under optimal AA content and ratio the replacement chickens at the end of the growing period outweighed the chickens from control group by 140 g. We also studied the influence of different content of AA and temporal changes in their ratio on digestibility of feed nutrients by replacement chickens from market egg flock. It was found that the optimal content of threonine and tryptophan and their ratio at certain periods of chicken growth caused the increase in digestibility of protein by 2 %, fiber – by 1 %, and BEV – by 2 %. We also proved that the decrease or increase of AA ratio in mix fodder of replacement chickens leads to the manifestation of antagonism between amino acids and the deterioration of their function in bird organism. The changes in AA ratio had significant effects on chicken productivity, the digestibility of feed nutrients, the assimilation, and efficiency of amino acid use. This effects were considerably stronger than the effect of changes in AA content. The degree of influence of the ratio between threonine and tryptophan varies throughout the growing period, it has been established that the ratio of threonine to tryptophan in the period of limited chick feeding (9-6 weeks) has a lesser effect on the productivity of repair young (R<sup>2</sup> = 0.89) the second one (R<sup>2</sup> = 0.92) and the last growing periods (R<sup>2</sup> = 0.92). We performed a mathematical model (polynomial trend line) to describe the growth of replacement chickens during all experiment periods, the pattern of dependences between chicken organism and AA content, AA ratio, age, and productivity. This nonlinear model is more relevant and reliable than linear dependence.</p>

scholarly journals Lactate Control Enhances Growth Advantage in Fed-batch Cultures of Metabolically Engineered CHO Cells with Reduced Novel Growth-inhibitory Compound Formation

2021 ◽  
Author(s):  
Quentin Bethune ◽  
Cameron Harrington ◽  
Bhanu Mulukutla
Keyword(s):  
Amino Acid ◽  
Cho Cells ◽  
Fed Batch ◽  
Compound Formation ◽  
Knock Out ◽  
Batch Cultures ◽  
Growth Inhibitory ◽  
Inhibitory Compound ◽  
Cell Densities ◽  
Produce Amino Acid

CHO cells have been recently shown to produce amino acid catabolism derived byproducts, which accumulate in fed-batch cultures to growth-inhibitory levels. Residual amino acid limitation or genetic engineering strategies have been successfully employed to suppress production of these novel growth inhibitory metabolic byproducts. However, the growth advantage attained due to suppression of these metabolic byproducts in fed-batch cultures is more pronounced when lactate accumulation is also controlled. BCAT1 knock-out (KO) CHO cells, which produce negligible levels of the metabolic byproducts isovalerate, isobutyrate and 2-methylbutyrate, grow to significantly higher peak cell densities in fed-batch cultures with lactate control (HiPDOG) as compared to cultures without lactate control. Henceforth, strategies involving novel metabolic byproduct control should preferably include lactate control to more easily assess the enhanced cell growth and productivities attainable.

scholarly journals Amino Acid Requirements of the Chinese Hamster Ovary Cell Metabolism during Recombinant Protein Production

2019 ◽  
Author(s):  
Bergthor Traustason
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Recombinant Protein ◽  
Recombinant Proteins ◽  
Chinese Hamster Ovary ◽  
Cho Cells ◽  
Chinese Hamster ◽  
Ovary Cell ◽  
Scale Model ◽  
Amino Acid Requirements

SummaryMajority of biopharmaceutical drugs today are produced by Chinese hamster ovary (CHO) cells, which have been the standard industry host for the past decades. To produce and secrete a substantial amount of the target recombinant proteins the CHO cells must be provided with suitable growth conditions and provided with the necessary nutrients. Amino acids play a key role in this as the building blocks of proteins, playing important roles in a large number of metabolic pathways and being important sources of nitrogen as well as carbon under certain conditions. In this study exploratory analysis of the amino acid requirements of CHO cells was carried out using metabolic modelling approaches. Flux balance analysis was employed to evaluate the optimal distribution of fluxes in a genome-scale model of CHO cells to gain information on the cells’ metabolic response in silico.The results showed that providing non-essential amino acids (NEAAs) has a positive effect on CHO cell biomass production and that cysteine as well as tyrosine play a fundamental role in this. This implies that extracellular provision of NEAAs limits the extent of energy loss in amino acid biosynthetic pathways and renders additional reducing power available for other biological processes. Detailed analysis of the possible secretion and uptake of D-serine in the CHO model was also performed and its influence on the rest of the metabolism mapped out, which revealed results matching various existing literature. This is interesting since no mention of D-serine in regard to CHO cells was found in current literature, as well as the fact that this opens up the possibility of using the model for better understanding of certain disorders in higher up organisms that have been implicated with D-serine, such as motor neuron and cognitive degeneration. Finally, outcome from the model optimisation of different recombinant proteins demonstrated clearly how the difference in protein structure and size can influence the production outcome. These results show that systematic and model-based approaches have great potential for broad de novo exploration as well as being able to handle the cellular burden associated with the production of different types of recombinant protein.

scholarly journals Neuropeptide FF (FLFQPQRF-NH2) and its Fragments Bind to α2δ Subunit of Voltage-Gated Calcium Channels

2019 ◽  
Vol 22 ◽  
pp. 292-300
Author(s):  
Hanna Skubatz
Keyword(s):  
Cerebral Cortex ◽  
Amino Acid ◽  
Cho Cells ◽  
New Drugs ◽  
Rat Cerebral Cortex ◽  
Amino Acid Residues ◽  
C Terminus ◽  
Neuropeptide Ff ◽  
Α2δ Subunit ◽  
Ca2 Channels

Purpose: Gabapentin, a drug for neuropathic pain, exerts its therapeutic effect via inhibition of the a2d subunit of N-type Ca2+ channels. Thus, finding peptides that specifically displace gabapentin from its binding site may lead to the development of new drugs. Methods: Displacement of bound [3H]-gabapentin in membrane preparations of rat cerebral cortex and of human Cav2.2/β3/α2δ1 expressed in CHO cell line. Results: Neuropeptide FLFQPQRF-NH2 specifically displaced bound [3H]-gabapentin in membrane preparations from rats and CHO cells. Truncation of the C-terminus of FLFQPQRF-NH2 by three amino acid residues to produce FLFQP-NH2 improved the displacement of gabapentin. FLFQP-NH2 displaced bound  [3H]-gabapentin with IC50 and Ki values of 2.7 µM and 1.7 µM, respectively. Deletion of two amino acid residues (FQ) in the middle of the FLFQP-NH2 sequence yielded FLP-NH2 that displaced bound [3H]-gabapentin with a lower affinity.  IC50 and Ki values were 11.9 µM and 7.8 µM, respectively. Neutral binding cooperativity existed when of FLFQP-NH2, FLP- NH2 and gabapentin when incubated together. FLFQPQRF-NH2 but not FLFQP-NH2 displaced bound [3H]-gabapentin to membrane preparations of human Cav2.2/b3/a2d1 expressed in CHO cells. Conclusion: FLFQPQRF-NH2, FLFQP-NH2 and FLP-NH2 displace bound gabapentin in membrane preparations of rat cerebral cortex. Binding cooperativity was detected when GBP/FLFQP-NH2/FLP-NH2 were incubated together. These novel binding sites may provide new approaches to modulate L-type Ca2+ channels.

Sign in / Sign up

Export Citation Format

Share Document