time, determining differentiation, growth, proliferation metabolism and behaviors as well as apoptosis of the cell Actually, DNA replication, transcription, and RNA processing all take place within the nucleus, with only the final stage of gene expression(translation) localized to the cytoplasm. The presence of the nucleus provides opportunities for the control of gene expression at the level of transcription, such as by the regulated transport of transcription factors, and allows gene expression to be regulated by posttranscriptional mechanism, such as alternative splicing. The separation of the genome from the site of mRNa translation thus plays a central role in eukaryotic gene expressiontime, determining differentiation, growth , proliferation, metabolism and behaviors as well as apoptosis of the cell. Actually, DNA replication, transcription, and RNA processing all take place within the nucleus, with only the final stage of gene expression (translation) localized to the cytoplasm. The presence of the nucleus provides opportunities for the control of gene expression at the level of transcription, such as by the regulated transport of transcription factors, and allows gene expression to be regulated by posttranscriptional mechanism, such as alternative splicing. The separation of the genome from the site of mRNA translation thus plays a central role in eukaryotic gene expression