By sending large numbers of polymerases to the wrong targets such a mutation may produce diseases that have no single cause, but are the result of hundreds and thousands of improper gene expressions that may seem functionally unrelated and, thus, render it almost intractable.
This provides an additional level of gene silencing that offers protection from the deleterious effects of improper meiotic gene expression during the mitotic cell cycle.
Such changes can lead to improper regulation of gene expression that could, in turn, result in cell transformation and cancer development.
Faulty embryonic methylation of DNA due to abnormal folate levels or improper methyl cycle gene expression at a critical developmental juncture could inappropriately silence growth factors necessary for proper tube closure.
Failure of chromosome pairing might lead to improper regulation of Hsp70Ba gene expression and hence hyperactivation in the Df 3R ED5579/DSK001.
As a consequence, an improper handling of multiple gene expression profiles obtained in different experimental settings would capture similarities in these settings rather than in the represented biological states (a phenomenon known as the 'batch effect' [57]).
Micro-RNAs silence gene expression by improper binding to a specific or to multiple mRNA sequences into a ribonucleoprotein called RISC (RNA-associated silencing complex).
It is therefore not surprising that 3′end formation represents a crucial regulatory step in eukaryotic gene expression and improper 3′end processing of pre-mRNAs is associated with a number of human diseases (Danckwardt et al, 2008).
In order to gain awareness of the gene expression artifacts linked to improper tissue handling also for this particular type of neoplasia, we have investigated gene expression profiles in a set of primary breast tumors, grossly subdivided into 4 aliquots and kept at room temperature for 0, 2, 6 and 24 hours after resection before snap-freezing in liquid nitrogen.
In the case of embryos produced by SCNT, besides the alterations due to in vitro culture conditions, gene expression defects may be caused by improper silencing and activation of specific genes, altered chromatin remodelling, and epigenetic alterations [ 41].
