For the model system organism Caenorhabditis elegans, microinjection is a common technique used for DNA transformation. This technique is powerful to assemble genetic and molecular analysis to phenotypic analysis, facilitating the transgenic expression of genes, and the implementation of technologies, such as clustered regularly interspersed short palindromic repeats (CRISPR)-Cas9 system and RNA interference (RNAi). Therefore, we offer the C. elegans microinjection service to meet the specific needs of customers.
The microjection procedure is administered through the reproductive system of C. elegans. The reproductive tract of C. elegans hermaphrodites exhibits bilobed symmetry. Each gonad arm is U-shaped and composed of a uterus (the proximal region), spermatheca, proximal oviduct, and ovary (the distal region). The distal region of each gonad, termed the syncytial arm, is the origin of the germline. Oocytes mature in an assembly-line fashion in the oviduct and fertilized in the spermatheca by hermaphrodite-derived sperm or male-derived sperm. Subsequently, partial embryonic development occurs in the uterus. Thus, the correct site performed microinjection for genetic transformation in C. elegans is the syncytial gonad, which ensures the incorporation of injected DNA into the nuclei of oocytes, and finally inherited through the fertilized egg.
Since Kimble et al. first performed the transformation through the microinjection of the gonad of C. elegans hermaphrodites. The protocol of this technique has been optimized and standardized by subsequent several key studies. At present, DNA microinjection is typically coinjected with easily scorable markers, the choice of which depends on the background of C. elegans strain. Most commonly used makers include rol-6, a dominant marker encoding cuticle collagen, and the pharyngeal expression of green fluorescent protein (GFP) or red fluorescence (mCherry).
Microinjection scheme for C. elegans hermaphrodite
In our C. elegans microinjection platform, several different DNA samples are available to be used for transformation, including plasmid, phage DNA, fosmid or cosmid DNA, and PCR product with your genes.
The process of transformation involves a complex rearrangement of the injected DNA into a single, large, multimer of the various DNA species injected. And the efficiency of transformation depends on the specific gene as well as the size of the recombined transgene. Previous studies have revealed that the transmission efficiencies can range from almost 90% to as low as 1-2%. Herein, in order to score for stably transmitting lines, we leave the transformed F1 progeny to self-fertilize for several days. For over-expressing or ectopically expressing genes, we offer at least three independent stable lines for phenotypic analysis. With regard to CRISPR/Cas9 site-directed mutagenesis, the other maintenance and selection criteria are applied.
CD BioSciences is a professional C. elegans model service provider. Microinjection is an essential tool for C. elegans research, involving creating transgenic worms, for RNAi of selected genes, and readily adapted for introducing various types of molecules directly to various locations. With our advanced equipment and scientists with years of experience, we are confident to offer our customers with high-quality data delivery, in-depth scientific and technical support. Please don't hesitate to contact us for more details.
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