Regulation of Eukaryotic Gene Expression

  Regulation of Eukaryotic Gene Expression Question 1The histone code is identified as a hypothesis in which the hypothesis of genetic information encoded in DNA that is in part regulated by the chemical modifications to the histone proteins mostly on their free ends. Similarly, with the alterations such as DNA methylation it is identified as being epigenetic code. For example, H3K9ac, and H3K27ac. The hypothesis in the other hand is guided by a chromatin-DNA movement that ensures combinations of histone modifications. The histone code is a complex structure that has been simplified. To give a general outlook about its complexity the Histone H3 has more than nineteen lysines that are identified to be methylated. Hence, every nucleosome in the cell can be identified to belong to different set of alterations, this in turn raises the question of the histone alterations indeed exists. Question 2Some specific- DNA binding sequence activate transcription. For example, they may assist in the overall transcription factors/ or the RNA polymerase that binds to the promoter. Transcription mechanisms ensures that there is a proper regulation of the transcription of genes when they copy to the RNA when making a protein. For a gene to become transcribed. The enzyme RNA polymerase, which is identified in making new RNA molecule obtained from the DNA template. It has to get attached to the DNA of the specified gene, as it gets attached to a spot known as the promoter. Question 3 After the occurrence of transcription, gene expression may still be regulated in different stages. Proteins that are identified as transcription factors play a significant role in the regulating transcription. These specific proteins ensure that the genes remain active in each cell of the body. Some of the transcripts can have the alternative splicing, this process propagates the different mRNAs and protein using the same RNA transcript. Some of the mRNAs can be targeted by the microRNAs, thus small regulator RNAs leads to an MRNA being removed or block translation. The activity of the protein can be regulated even after translation, for example removing the amino acids or subsequent addition of chemical groups. When the eukaryotic is transcribed in the nucleus the RNA molecule that has been freshly created cannot be considered as a messenger RNA. It belongs to a molecule identified as pre-mRNA.  The premRNA has to pass through different modification. These can include capping, splicing and the additional of a poly-A tail, that can be technically regulated, sped up, altered or even slowed down, thus resulting in a different scenario. a. Alternative splicing: for this type of transcription. The different sections of the mRNA are chosen to be used as exons. The process allows for more molecules to be made from a single strand of pre-mRNA. The process is not random, rather happens in a specific mode. The process is mainly controlled by proteins specialized for regulation purposes.  b. Phosphorylation: in this mode of transcription, a phosphate group attaches itself to a protein. The protein is then activated by the process of phosphorylation. At the same time, others are deactivated to enable them change their functioning. c. Ubiquitination: In this transcription process, the ubiquitin-tagged proteins are engaged by the proteasome and later broken down into their component parts.