MBB331_Week10-Fall-2011

2 45 drosophila specialized chromatin structures

Info iconThis preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: I hypersensitive in RBCs or lymphocytes or α -2 globin genes & flanking -2 sequences nucleosome-free, and expressed, in RBCs expressed, 44 Weaver 2002 Molecular Biology Ed. 2 INSULATORS INSULATORS • • • Insulator placed between Insulator enhancer & promoter - insulator blocks enhancer action on promoter; likely explanation for limitation of enhancer activity to particular promoter to Position effect variegation: Position active genes repressed when placed next to heterochromatin (condensed chromatin) placing insulator between heterochromatin & gene blocks spreading inactive condensed chromatin chromatin Models: insulators loop & Models: restrict DNA domains or block factor sliding factor Weaver 2002 Molecular Biology Ed. 2 45 Drosophila SPECIALIZED CHROMATIN STRUCTURES STRUCTURES Lewin Genes VII 2000 Oxford University Press flanking scs & scs´ flanking scs sequences insulate Drosophila hsp70 genes from effects of surrounding genes genes scs sequences resistant to DNase I resistant degradation, flanked by adjacent hypersensitive site hypersensitive -scs placed on either side of Drosophila white gene (for red eyes) ensure gene white function anywhere in genome, even when inserted into heterochromatin function 46 scs BINDING PROTEINS scs Lewin Genes VII 2000 Oxford University Press • Red = DNA, Green = BEAF32, Yellow = overlap Green Yellow • BEAF32 binds at scs insulator sites located at scs ~50% of Drosophila polytene c...
View Full Document

Ask a homework question - tutors are online