Effect of Ionizing Radiation on the Transcript Variants Expression of p21 Gene.

PURPOSE: CDK1A is one of the most important genes that have different key roles in cell lines. This gene has several transcript variants. Investigating of expression of each one actually can be so important because any one of them may have a separate unknown role in cancer cells so can be used to increase therapeutic efficacy. METHODS: A549, MDA-MB-231 and Hek-AD cell lines were used in this study. Firstly, three primers for variants of p21 gene were designed by Snapgene and BLAST software. Secondly, the variants expression was checked for each cell lines by RT-qPCR technique, separately. Then the variants that expressed in the cells were selected for more investigation. Finally 2 Gy irradiation was used to evaluate the effect of that on variants expression. RESULTS: The results show that for all cell lines, primer num1 and 3 expressed before any stimuli. After irradiation, for MDA-MB-231 and A549, the expression of primer num3 was decreased, while for Hek-AD no change was observed. The primer num1 expression after the irradiation was different for the cells, V1 expression was decreased in A549 by fold of 0.03 while expression of this for MDA-MB-231 cells was not changed after 2Gy irradiation. CONCLUSION: It is very necessary to pay attention to the function of each splice variant as well as the response to external stimuli. Understanding the role of each variant in a gene is critical and researchers can use that to improve radiotherapy as well.

Radiation target analyses of DNA template/primer complexes.

Frozen solutions of low molecular weight DNA template/primer complexes, in the absence and presence of HIV-1 reverse transcriptase, were irradiated with high-energy electrons. Molecules that survived the radiation exposure were quantified and analyzed using radiation target theory. Transfer of radiation-deposited energy was observed by the damage caused. It was found that damage (as a polynucleotide chain break) was observed in one chain when the radiation interaction occurred in the other chain, suggesting a transfer of energy. In contrast, the target sizes of the DNA template/primers were not altered if bound to HIV-1 reverse transcriptase, signifying that the deposited radiation energy is not transferred between protein and nucleic acid.