Table 1 Overview of examples of (heterologous) protein production which lead to one of the above described stress symptoms (decreased growth rate, impaired protein production, genetic instability or an aberrant cell size)
Stress symptom | Engineering strategy | Possible mechanisms involved | Solution provided | References |
|---|---|---|---|---|
Decreased growth rate | Plasmid-based inducible expression: | - Heat shock response | Dynamic expression of a sgRNA for target sequence under control of hptG1 promoter identified to be upregulated | [127] |
- Reporter | - Stringent response | |||
- Large heterologous proteins | ||||
- Operon encoding a metabolic pathway | ||||
Decreased growth rate | Production of membrane proteins (GarP and YidC) | - Cpx stress response | sRNA based genetic circuit: | [94] |
Impaired protein synthesis | - Stringent response | - Improved growth& protein production | ||
Aberrant cell size | - Aggregation of MinD | - Filamentation persisted | ||
Decreased growth rate | Production of membrane proteins (YidC, YedZ, LepI) | - Overloaded Sec translocon | [74] | |
Impaired protein synthesis | - Phage shock response | |||
Aberrant cell size | - Aggregation of MinD | |||
Impaired protein synthesis | Production of periplasmic proteins (Single-chain antibody fragment BL1) | - Overloaded Sec translocon | Lowering expression levels resulted in a decreased cell size & decreased amount of aggregates\(\backslash\)inclusion bodies | |
Genetic instability | - Heat shock response | |||
Aberrant cell size | - Phage shock response | |||
- Envelope\(\backslash\)General stress response | ||||
Decreased growth rate | Expression of plant proteins | - Compromised protein folding | - Determining the amount of rare codons to select most suitable host | [13] |
Impaired protein synthesis | - Stringent response | - Adding tRNAs of rare codons was detrimental to growth and protein solubility | ||
(Depletion of charged tRNAs and translation speed) | ||||
Genetic instability | Two synthetic genetic circuits (Induced by either AHL or IPTG) | - Recombination of repeated sequences | - Lower expression level to reduce metabolic load & thus mutation rate | [128] |
- General stress response | - Avoid use of repeated sequences in genetic circuits |