2010-12-20, 06:02 PM
Thread is now about the effects of microRNA on mRNA transcription and Final Fantasy. Both topics are fair game.
Final Fantasy: Clash on Big Bridge:
[video=youtube;NKwqMZd6zhw]http://www.youtube.com/watch?v=NKwqMZd6zhw[/video]
Alcohol kills off neurons in your brain thus resulting in tolerance: (written by Swerve)
Andrzej Pietrzykowski presented his research on the relationship between alcohol tolerance and post-transcriptional regulation of mRNA. In order to study this relationship, the BK channel was selected as the subject of interest. The BK channel is located in the human brain and is responsible for regulating neurons that influence the release of chemical and electrical signals. Varied potentiation for each BK channel is due to alternative splicing of its α subunit, resulting in functional diversity. The presentation focused on alcohol upregulation of miR-9, a microRNA that binds to the 3’UTR of alcohol sensitive mRNA and proceeds to rapidly cleave the molecule in order to render it useless. Loss of particular mRNA transcripts results in BK channel modification that causes alcohol tolerance.
In order to assess the natural state of the brain before alcohol exposure, end-point polymerase chain reaction was applied to neurons from the supraoptic nucleus in order to identify alternative spliced exon sites. After sequencing, it was discovered that the mRNA transcripts contained eight different variations of exonal compositions with exon 29 being prevalent in five of the eight transcripts. However, when the neurons were exposed to alcohol, the eight different variations were reduced to only two and neither contained exon 29. Therefore exon29 became known as ALCOREX (alcohol regulated exon) due to its absence after exposure to alcohol. In order to examine quantitative changes in mRNA due to alcohol exposure, qRT-PCR indicates that the total BK mRNA was significantly downregulated because ALCOREX mRNA was sharply reduced along with other splice variants.
The reduction in ALCOREX mRNA coincided with an increase of miR-9 in the alcohol exposed neurons therefore indicating that the two factors are connected. MicroRNA functions by binding to miRNA Recognition Element (MRE) located in the 3’ untranslated region of most mammals. As stated previously, it is known that ALCOREX mRNA is significantly reduced in comparison to other splice variants. If miRNA is responsible for the dramatic reduction of ALCOREX mRNA, then it is possible that ALCOREX mRNA contains a characteristic MRE that distinguishes itself from the other two mRNA transcripts that did not contain exon 29 after alcohol exposure. Primers revealed that there were three major MRE sequences in the 3’UTR region with no alcohol exposure: 3’UTR-2.1 (90% of total 3’UTR), 3’UTR-2.2 (10% of total 3’UTR), and 3’UTR-1.0 (hardly detectable). When the neurons were exposed to alcohol, miR-9 specifically targeted the 3’UTR-2.1. Further experimentation revealed that ALCOREX contains only 3’UTR-2.1 MRE in its 3’UTR region, while other sequences such as STREX contained both 3’UTR-2.1 and 3’UTR-2.2 in equal amounts. Therefore this explains the target reduction in ALCOREX when exposed to alcohol.
Reduction of ALCOREX mRNA results in alcohol tolerance as the exon is the most sensitive when it comes to alcohol exposure. Neurons containing BK channels with high amounts of ALCOREX have the greatest potentiation and have the longest duration when it comes to signal transmission. Loss of ALCOREX results in reduced BK Channel potentiation and duration, therefore resulting in alcohol tolerance for neurons in the brain.
Final Fantasy: Clash on Big Bridge:
[video=youtube;NKwqMZd6zhw]http://www.youtube.com/watch?v=NKwqMZd6zhw[/video]
Alcohol kills off neurons in your brain thus resulting in tolerance: (written by Swerve)
Andrzej Pietrzykowski presented his research on the relationship between alcohol tolerance and post-transcriptional regulation of mRNA. In order to study this relationship, the BK channel was selected as the subject of interest. The BK channel is located in the human brain and is responsible for regulating neurons that influence the release of chemical and electrical signals. Varied potentiation for each BK channel is due to alternative splicing of its α subunit, resulting in functional diversity. The presentation focused on alcohol upregulation of miR-9, a microRNA that binds to the 3’UTR of alcohol sensitive mRNA and proceeds to rapidly cleave the molecule in order to render it useless. Loss of particular mRNA transcripts results in BK channel modification that causes alcohol tolerance.
In order to assess the natural state of the brain before alcohol exposure, end-point polymerase chain reaction was applied to neurons from the supraoptic nucleus in order to identify alternative spliced exon sites. After sequencing, it was discovered that the mRNA transcripts contained eight different variations of exonal compositions with exon 29 being prevalent in five of the eight transcripts. However, when the neurons were exposed to alcohol, the eight different variations were reduced to only two and neither contained exon 29. Therefore exon29 became known as ALCOREX (alcohol regulated exon) due to its absence after exposure to alcohol. In order to examine quantitative changes in mRNA due to alcohol exposure, qRT-PCR indicates that the total BK mRNA was significantly downregulated because ALCOREX mRNA was sharply reduced along with other splice variants.
The reduction in ALCOREX mRNA coincided with an increase of miR-9 in the alcohol exposed neurons therefore indicating that the two factors are connected. MicroRNA functions by binding to miRNA Recognition Element (MRE) located in the 3’ untranslated region of most mammals. As stated previously, it is known that ALCOREX mRNA is significantly reduced in comparison to other splice variants. If miRNA is responsible for the dramatic reduction of ALCOREX mRNA, then it is possible that ALCOREX mRNA contains a characteristic MRE that distinguishes itself from the other two mRNA transcripts that did not contain exon 29 after alcohol exposure. Primers revealed that there were three major MRE sequences in the 3’UTR region with no alcohol exposure: 3’UTR-2.1 (90% of total 3’UTR), 3’UTR-2.2 (10% of total 3’UTR), and 3’UTR-1.0 (hardly detectable). When the neurons were exposed to alcohol, miR-9 specifically targeted the 3’UTR-2.1. Further experimentation revealed that ALCOREX contains only 3’UTR-2.1 MRE in its 3’UTR region, while other sequences such as STREX contained both 3’UTR-2.1 and 3’UTR-2.2 in equal amounts. Therefore this explains the target reduction in ALCOREX when exposed to alcohol.
Reduction of ALCOREX mRNA results in alcohol tolerance as the exon is the most sensitive when it comes to alcohol exposure. Neurons containing BK channels with high amounts of ALCOREX have the greatest potentiation and have the longest duration when it comes to signal transmission. Loss of ALCOREX results in reduced BK Channel potentiation and duration, therefore resulting in alcohol tolerance for neurons in the brain.