Fusion point mutation

RET Point mutations, fusions Thyroid, parathyroid, adrenal... 

Usually introduction of a point mutation is desired to occur in the middle of the target gene and not at the N- or C-terminal end, for which the primers are normally designed. To ensure that both DNA strands will carry the mutation, a fusion PCR can be performed. 

Figure 10.1 Fusion PCR, an early method to introduce point mutations in site-directed mutagenesis.

Nrg1tm2Cbm Targeted mutation 2, Carmen Birchmeier Exon 8 is fused to a lacZ gene. Coding sequences downstream of the fusion point, including the N-terminal half of the EGF domain, are deleted... 

Identification of the amino acid sequence to be modified requires knowledge not only of the existing function but, importantly, also of the desired new or improved function. This alteration can be achieved through single-point mutations, exchange of the whole domains, or by the generation of fusion proteins [4]. When these changes have been made, the mutants are purified and evaluated. 

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