Functional Regulation of Baculovirus Homologous Region by Cellular microRNAs of Silkworm Bombyx mori
| Autor: | Hsu-Min Sung, 宋旭民 |
|---|---|
| Rok vydání: | 2012 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 100 Individual baculovirus homologous region (hr) contains 2 to 8 tandem repeats of imperfect palindrome sequence and has been proved to function as a transcriptional enhancer in both insect and mammalian cells. Besides, it can function as a replication origin in a virus-dependent manner. In this study, we found that when the microRNA (miRNA) pathway was abolished, the replication of AcMNPV could increase significantly in non-host BmN cells; therefore, possibility exist that certain miRNAs in BmN cells might suppress the functions of hrs and block the replication of the virus. With the aid of in silico prediction, we identified 10 Bombyx mori cellular miRNAs with potential binding sites on hr. Reporter assay and qPCR studies showed that the function of hr as a transcriptional enhancer and replication origin were both significantly suppressed by certain Bombyx mori miRNAs. Those miRNAs can significantly suppress the function of hr were predicted to have high binding scores against the palindrome sequence of hrs. Two of these miRNAs, bmo-2808a and bmo-2808b, were both predicted to have multiple binding sites on the viral DNA (hr1, hr2, hr3, hr4, hr5). It was proven that the binding of IE1 on palindrome sequence is important for hr to display its full function; therefore, it is reasonable for us to propose that bmo-2808a and bmo-2808b might suppress the function of hr via occupying the IE1 binding sites on palindrome sequence. This hypothesis is supported by our observation that the number of IE1 foci in the nucleus is decreased when co-transfected with either bmo-2808a or bmo-2808b, indicating these miRNAs function as inhibitors to keep IE1 away from its binding sites on hr. Although further experiments are still needed, our results may have identified a novel role of miRNA to the functional regulation of DNA replication and / or enhancing of transcription. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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