The Authors’ Question
The article Activator Control of Nucleosome Occupancy in Activation and Repression of Transcription by Bryant et al. delves on a highly studied area on the relationship between chromatin structure and gene expression (par.1). In this study, the authors assert that the universal activator, namely the Gal4, helps to remove promoter nucleosomes.
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In the process, it triggers the transcription of information. However, the way the activator performs this function is a least known process. This gap has been the subject of debate in many studies. To study this area, the research paper focuses on two questions, which include:
- Is the reformation of promoter nucleosomes required for gene silencing?
- Does Gal4 perform its task in sync with galactose and glucose?
A hypothesis is a central part of a research paper since it guides the process of proving or disapproving any author’s assumptions in a given research. In the article under study, Bryant et al. draw their hypotheses from the research questions (par.3). The hypotheses include:
- The reformation of promoter nucleosomes is required for gene silencing
- Gal4 continues to function in the presence of galactose and glucose
What they Did to Test the Hypotheses
To test their hypotheses, Bryant et al. used the experimentation method where they applied the quantitative micrococcal nuclease protection assay (par.4). The method is essential in the measurement of any specified DNA fragment together with the population that is covered or occupied by a nucleosome in vivo. Using this method, the authors seek to show that Gal4 recruits SWI/SNF in early steps of gene activation.
Subsequently, it quickly removes the promoter nucleosomes. The authors also show that when SWI/SNF is not available, an augmented degree of gene recording is witnessed. Besides, the gene boosters are freed from nucleosomes.
Once the relocation of body components from galactose to glucose is done, the recording process reduces. Nevertheless, once glucose is included in the cells that develop in galactose, the change of nucleosomes does not occur swiftly, even though mRNA manufacturing reduces.
Following the experiments, the results reveal the nuclease sensitivity in and around GAL1 10 UASg. The experiment shows that transcriptional machinery does not protect the digestion of micrococcal nuclease. These findings correlate with the previous studies that have used micrococcal nuclease.
In terms of the sensitivity of nuclease around GAL1 10UASg, the experiment reveals that each member of the population has its DNA segments well protected. According to the article, the protection follows the presence of a molecule that is bound to UASg. Further, the experiment shows that SWI/SNF is a requirement for the rapid removal of nucleosome.
Besides, the experiment confirms that any delay in the removal of nucleosome causes a corresponding interruption of the onset of the transcription process. Such findings are contrary to the previous studies that have claimed that the mutation of SNF2 does not have any influence and effect on the transcription process of GAL genes.
What the Results Mean
The results of the study indicate that the reorganization of nucleosomes is not compulsory for subjugation or DNA suppression. Further, the results signify that the GAL4 continues to function in the presence of galactose and glucose.
The findings effectively disapprove previous results that have suggested that SNF2 does not have any influence on the transcription of GAL genes. Thus, the research opens a new area of knowledge that needs further investigation to find the reason GAL2 continues to function in the presence of galactose and glucose and the main aim of such function.
Bryant, Gene, Vidya Prabhu, Monique Floer, Xin Wang, Dan Spagna, David Schreiber, and Mark Ptashne. Activator Control of Nucleosome Occupancy in Activation and Repression of Transcription, 2008. Web.