The authors suspected that the ISX element had a strong recruitment signal for the MSL complex, but they needed to verify whether the ISX element attracts the MSL protein complex, and if it does, how strongly it does so.

How did the authors test the hypothesis that the ISX element formed an MSL recognition element (MRE) with a strong recruitment signal for the MSL protein complex, thereby enabling ISX to function as a chromatin entry site in a living organism (in vivo)?

Select all that apply.

(a)They investigated the genomic distribution of transposons ISY and ISX and found that ISX was located mainly on the neo-X chromosome.

(b)They mutated ISX to ISY by inserting the missing 10-basepair sequence, inserted it into an autosome of D. melanogaster, then used immunostaining to see if the MSL complex would bind.

(c) They used chromatin immunoprecipitation-quantitative polymerase chain reaction to measure the affinity of the MSL complex for ISX and ISY.

(d) They mutated ISY to ISX by deleting the 10-basepair sequence, inserted it into an autosome of D. melanogaster, then used immunostaining to see if the MSL complex would bind.

(e)They inserted copies of ISX and ISY into an autosome of D. melanogaster and used immunostaining to see if the MSL complex would bind to them.