Complex sentence: Repression of gene transcription is acheived by the reverse of this mechanism, where the actylation is removed by one of the HDACs and allows histone to interact with DNA to form compacted nucleosome assembly.
Split into simpler sentences: Repression of gene transcription is achieved by the reverse of this mechanism. Where the acetyl group is removed by one of the HDACs during deacetylation allows histones to interact with DNA more tightly to form compacted nucleosome assembly.