Looking to add a tag to your protein of interest ?

Let our team create your custom knock-in line.

Genome ProLab can help you introduce a defined DNA sequence into a selected genomic location in Drosophila melanogaster. From small epitope tags such as HA and FLAG to fluorescent proteins such as GFP, we tailor the strategy to your gene and research objectives.

How Are Knock-in Alleles Generated ?

CRISPR-Cas9 uses a guide RNA (gRNA) to direct Cas9 to a selected genomic sequence. Cas9 creates a double-strand break near the intended insertion site.

A donor DNA template, containing the desired insertion flanked by sequences matching the target region, is provided. Through homology-directed repair (HDR), the cell can use this template to incorporate the new sequence into the genome.

This approach allows a tag or other DNA element to be introduced at a defined position within an endogenous gene.

Small Tags and Larger Insertions

Epitope tags — HA, FLAG and more

Small epitope tags can facilitate protein detection, immunoprecipitation, and other antibody-based applications. Depending on the gene and experimental goals, a tag may be placed at the N-terminus, C-terminus, or a suitable internal position.

Fluorescent proteins — GFP and other reporters

Larger insertions, such as GFP, can support studies of protein localization and expression. Tag placement and construct design are important to help preserve the function and regulation of the targeted protein.

A Strategy Tailored to Your Project

The most suitable approach depends on the insertion size, the target site, the gene’s structure, and the available genetic resources.

 Selecting the insertion site

We consider the relevant transcripts, protein domains, and your preferred tag position when assessing the project. For protein fusions, the design must preserve the reading frame and may include a linker between the protein and its tag.

Choosing the gRNA and donor design

Suitable gRNAs must target a region close to the intended modification. Existing gRNA resources may be considered when appropriate; otherwise, custom guides and a donor template can be designed for the project.

Planning for multiple tags

If you want several alternative tags inserted at the same position in the same gene, let us know at the outset. A coordinated strategy may help reduce duplicated work and overall project costs.

Molecular Verification

We verify the complete inserted sequence and both genomic junctions by DNA sequencing to confirm the intended integration.

Tell Us About Your Knock-in Project

Provide your gene name or FlyBase ID, the desired tag or insertion, your preferred insertion position, and any relevant fly stocks or plasmids you already have.

For GFP or another specific tag variant, we may ask you to supply a plasmid carrying the exact sequence you want incorporated.

Our team will review your project and provide a proposed strategy and a customized quote.