How does the nucleus control gene expression?

The nucleus controls gene expression through various processes. One process is transcriptional regulation, which is the synthesizing of RNA molecules from DNA templates. Transcriptional regulation involves the binding of transcription factors and regulatory proteins, as well as promoters and enhancers. Promoters and enhancers may activate or repress the transcription of genes, thus controlling the production of specific RNA molecules. The nucleus also regulates gene expression through chromatin modification. Chromatin remodeling involves changes in the binding ability of DNA to transcription factors. The nucleus uses histone modifications to inhibit or promote gene expression. RNA processing is another way the nucleus controls gene expression. Modifications such as splicing, capping, and polyadenylation of mRNA molecules are all involved in RNA processing. These processes help produce mature mRNA molecules that can be transported to the cytoplasm for translation. The nuclear pore complex selects which RNA molecules move into and out of the nucleus, which may later affect which genes are to be expressed.