BIOC 4403 Lecture Notes - Lecture 4: Group Ii Intron, Mobile Genetic Elements, Group I Catalytic Intron
27 Mar 2017
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Document Summary
Mobile genetic elements: dna elements that encode proteins that mediate the movement of the element within a genome and between genomes. Found in all domains of life, abundant and dynamic. Mobile introns: intervening sequences that are capable of self-splicing and moving themselves within and between genomes (group i and group ii introns) Inteins: proteins that carry out protein splicing and are also capable of moving the gene that encodes them to other locations. Group i introns: mobile self-splicing ribozymes that catalyze their own removal from rna. Some contain an orf encoding a homing endonuclease (he) Intron removed by 2 transesterification reactions: 1st reaction initiated by oh of exogenous guanosine. Group i intron homing: the lateral (or horizontal) transfer of an intervening sequence (intron) into an intron-lacking version of the gene. Homing endonucleases (he): recognize and cleave 12-40bp dna sequence motifs, some also have a maturase function to help the intron fold into the 3d shape required for splicing.
