Lecture 6 - Lecture6

Info iconThis preview shows pages 1–2. Sign up to view the full content.

View Full Document Right Arrow Icon
Lecture 6 what is the difference between regular RNA splicing and Alternative splicing? alternative splicing is a subclass of RNA splicing only mRNA produced from any given pre-mRNA during splicing it doesn’t matter how many introns are removed, the RNA needs to have the correct sequences in some cases in a regulated fashion, genes can produce two or more different mRNA from the same primary RNA Why? how does it do that? does it make a mistake? No it does not make a mistake, there are regulatory proteins involved in reg- ulatory splicing that make it have unique proteins that either mask the splice junctions that normally would be used or you would have proteins that are weak splice junctions weak splice junctions - splice junctions that are not recognized very effi- ciently, they make other sequences look like a splice junction so you ac- tually get different sequences excised from the message in general, having alternative domains for proteins expressed or not. (in flies) in one lineage or sex, each step has a different splicing in the male and female organism so that in one case, the male specific splicing pattern generates a non-functioning pattern because it has a premature stop codon in the exon that is contained, in females the exon is deleted thereby having a functional protein. an exon and intron is dependent on knowing what the splice pattern is. The definition of what an exon or intron is, is merely what ends up in the mRNA assuming it’s not a genetic mutation. Alternative splicing is a regulated phenomenon whereby you can splice the mRNA alternative patterns, but they are not random If a given cell is Alternative splicing exclusive (meaning that if I have two variants of splicing can both of them coexist in the same cell, or does one cell make one and another cell make the other)? The cell can make more than one mRNA Depends on the unique splicing factors that are needed to mediate the specific splices RNA splicing - have a gene, that gene has sequence of nucleotides and a pro- moter. The promoter causes transcription and get integral pre-mRNA or primary transcript. This transcript resides in the nucleus. And to get out of the nucleus it is packaged by the proteins, then passing through complexes of the nuclear mem- brane called spliceosome. Introns are removed so that the mRNA form that is cap- able of being translated should end up in the cytoplasm where it will associate. Comparing the sequence of genomic RNA and the mRNA, if there is splicing going on you will see that sequences that are internal that have been deleted going from the genomic DNA, which looks like a copy of the pre-mRNA.
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 2
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 01/26/2009 for the course BIOLOGY 244 taught by Professor Palter during the Fall '05 term at Temple.

Page1 / 5

Lecture 6 - Lecture6

This preview shows document pages 1 - 2. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online