= Solution
\b[Use fluorescent <dCas9> to ask whether NVNA1 foci coincide with a defined host <DNA> locus.] Targeting a candidate repeated region with <CRISPR locus labelling> would produce a locus marker in a second colour. Reproducible colocalization with full-length NVNA1, but not with a labelled unrelated locus, supports sequence-associated accumulation. A non-targeting guide and <biological cells> lacking NVNA1 control <fluorescence> and targeting background; matched expression and nuclear localization control the <protein> comparison. The inactive <Cas9> is important because cleavage itself could create the <chromosome> damage being investigated.
A complementary causal test would alter the candidate host recognition region and ask whether focal accumulation is reduced while general nuclear NVNA1 remains. Independent edited clones, verification of the host alteration, and an appropriate restored host-site control would distinguish loss of recognition from clone-specific damage or copy-number changes. Colocalization localizes the <protein> but does not alone prove direct base-specific contact; the biochemical binding evidence supplies that separate argument. Fluorescent CRISPR marking of a repeated host locus has a direct precedent in the EBNA1 study.<Chromosomal fragile site breakage by EBV-encoded EBNA1 at clustered repeats by Julia Su Zhou Li and others>[Figure 2g–l: CRISPR locus labelling and colocalization controls]{ref}
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