Epigenetic+control

 **Epigenetic Control of Gene Expression**

Epigenetic control of gene expression refers to changes in the genome that can be inherited, but do not alter the DNA sequence itself (Yang and Schwartz 2011). Examples of changes that can be made are DNA methylation, noncoding RNA’s and histone modification (Yang and Schwartz 2011). Epigenetic marks are associated with environmental factors as well as aging and disease (Yang and Schwartz 2011).  This process shows us how things such as environmental factors can affect our genome. Epigenetic marks are also associated with a variety of diseases and cancers (Yang and Schwartz 2011), which opens up the door for research into epigenetic marks, their role in diseases such as cancer, better diagnostic methods, and possible treatments targeting epigenetic marks.  One disease that is linked to epigenetic control is asthma. The expression of inflammatory genes in the lung are linked to the acetylation of histones, and could lead to new therapeutic strategies to target the acetylation of histones to suppress inflammation (Barnes 2009). Barnes (2009)’s paper discusses the effect of acetylation of histones in the activation of inflammatory genes in the lungs which causes asthma. This study showed that some corticosteroids actually target this acetylation and therefore suppresses the inflammatory response. This study revealed that understanding epigenetic marks can lead to a better understanding of the causes of disease. It also reveals that there are potential treatments that can target these epigenetic marks to allow for better treatment strategies. Finally, it suggests that further research should focus on other possible histone modifications that could help develop new treatments for asthma that is resistant to corticosteroids.  Yang and Schwartz (2011)’s paper is a review article that summarizes what we know about epigenetic marks and their role in lung diseases such as asthma and chronic obstructive pulmonary disease. This paper points out that anyone researching lung diseases should focus on epigenetic marks in the lungs and that this knowledge could lead to better therapeutic strategies for the treatment of lung diseases.  Straying away from asthma, Png et al. (2011)’s paper shows that epigenetic marks are also implicated in cancer. They showed that a factor that causes breast cancer is the methylation of the microRNA-335 locus, and identified this locus as a tumor and metastasis suppressor gene. This could lead to better understanding of breast cancer as well as other cancers, and lead to therapeutic strategies that target anti-methylation of this locus.

**REFERENCES **


 * Barnes PJ ** (2009) Targeting the epigenome in the treatment of asthma and chronic obstructive pulmonary disease. Proc Am Thorac Soc **6(8)**: 693-696


 * Png KJ, Yoshida M, Zhang XHF, Shu W, Lee H, Rimner A, Chan TA, Comen E, Andrade VP, Kim SW, King TA, Hudis CA, Norton L, Hicks J, Massague J, Tavazoie SF **(2011) MicroRNA-335 inhibits tumor reinitiation and is silenced through genetic and epigenetic mechanisms in human breast cancer. Genes Dev **25**: 226-231


 * Yang IV, Schwartz DA **(2011) Epigenetic control of gene expression in the lung. Am J Respir Crit Care Med **183(10)**: 1295-1301