The histone methyltransferases enzymes prevents the access of transcription factors of R gene there by decreasing the activity of R gene.
Explanation:
Histone methyltransferase enzymes perform methylation or demethylation of a DNA sequence of a gene.
These enzymes can get the gene on or off by performing methylation or demethlylation of DNA sequence or gene.
They surround the gene to be transcripted by polyadenylation tail, this prevents the access of transcription factors to the gene, thereby preventing the transcription process and consequently no protein formed.
This way transcription of R gene decreases.
By methylating the DNA sequence it modifies the gene and inhibits transcription thereby decreasing or no enzymatic activity.
Transcription is the process by which RNA is produced from the DNA. Option D is correct. Histone methylation opens up chromatin at gene R so transcription factors can bind to DNA more easily.
Histone Methylation:
It is the process by which histone is methylated by the action of histone methyl transferase.
The transcription of the R gene is decreased when methyl transferase activity is inhibited. This means the nucleosome structure is not opened up yet. Hence, RNA polymerase is unable to bind with DNA.
Therefore, Histone methylation opens up chromatin at gene R so transcription factors can bind to DNA more easily.
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