BIOL 2344 Lecture Notes - Lecture 9: Dna Methyltransferase, Spliceosome, Half-Life
28 Sep 2017
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Document Summary
In housekeeping genes, cpg islands are unmethylated (hypomethylated) genes tend to be expressed in most cell types. Splicing increases information content: spliceosome recognizes 5" and 3" splicing sites and removes intervening intro, splicing factors modulate ability of spliceosomes to recognize or choose splice sites, 1. Some splicing sites inhibit ability of spliceosome to recognize splice site: 2. Some splicing factors enhance ability of spliceosome to recognize splice site. Stability of mrna: can be regulated so that its half- life is shortened or lengthened influence mrna concentration, 1. Epigenetics ~ inherited changes in phenotype (appearance) or gene expression caused by mechanisms other than changes in underlying dna sequence, hence name epi- (over, above) - genetics. Genomic imprinting: genetic phenomenon by which certain genes are expressed in parent of origin specific manner, ex. maternal imprinting ~ mother"s chromosome is inactive, ex. Paternal imprinting ~ father"s chromosome is inactive: consequence of methylation of dna 9cytosine bases) in sex specific manner.
