ZeGenesis – Genetic Services


transient-overexpression-mRNA-injection Transient Overexpression

ZeClinics genetic experts can investigate the result of overexpressing an endogenous gene or exogenous coding sequence (CDS) via mRNA injection in zebrafish embryos. It is a fast and very easy way to see if your gene of interest might have a phenotype (reverse genetic analysis), and warrant making a germline mutant/transgenic.

Transient overexpression experiments can be employed to mimic pathological conditions caused by aberrant protein expression and to quickly characterize the effect of this abnormal protein expression. Additionally, they can also be a useful strategy to restore the phenotypes observed in loss-of-function models.

Overexpression experiments will help establish a direct link between the biochemical function of a gene product and its role in vivo. Phenotyping is possible with good controls but the decreasing concentration of injected mRNA leads to sub-optimal KO usually by 4dpf.

mRNA injection for Transient Overexpression

Looking for a strategy to evaluate the effect of aberrant protein expression in pathological conditions?


  • Study how the aberrant expression of a protein affects a biological process at early developmental stages.
  • Reversion of phenotypes associated with gene loss-of-function.


Uniform protein overexpression at early developmental stages.

High throughput screening of multiple candidate genes

Non-invasive, in vivo readouts to detect gain-of-function-induced phenotypes at cell, tissue or organ levels.

Method description

To generate a model based on mRNA’s expression, zebrafish one-cell-stage embryos are injected with a solution containing the mRNA synthesized in vitro and encoding for the CDS of interest. During early stages of embryonic development, the plasmid can be imported in the nucleus and remain episomic. The exogenous CDS can be expressed by the promoter sequence included in the plasmid giving rise to F0 larvae transiently expressing the sequence of interest. The expression of the exogenous CDS can be associated with one fluorescent reporter to facilitate the phenotypic analysis of the models generated.

Figure 1.  Transient overexpression in embryos injected with an mRNA encoding for the gene of interest. Effect of mRNA expression can be readily analyzed during early development.


Results of the phenotypic analysis according to customers' interests and needs:

  • Teratogenic phenotypes
  • Organ-specific morphological or functional defects (heart-specific, liver-specific etc.)
  • Behavioral phenotypes

We'd like to hear from you

If you want more information about our mRNA
injection services or have any other questions,
please contact our experts.


  1. Liu Y, Lin Z, Liu M, Wang H, Sun H. Overexpression of DYRK1A, a Down Syndrome Candidate gene, Impairs Primordial Germ Cells Maintenance and Migration in zebrafish. Sci Rep. 2017 Nov 10;7(1):15313.
  2. Finckbeiner S, Ko PJ, Carrington B, Sood R, Gross K, Dolnick B, Sufrin J, Liu P. Transient knockdown and overexpression reveal a developmental role for the zebrafish enosf1b gene. Cell Biosci. 2011 Sep 26;1:32.
  3. Hogan BM, Verkade H, Lieschke GJ, Heath JK. Manipulation of gene expression during zebrafish embryonic development using transient approaches. Methods Mol Biol. 2008;469:273-300.