Myodmyod homodimer myodmyod homodimer active active

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: OTIFS HELIX­ A. B. Lewin Genes VII 2000 Oxford University Press • Heterodimers between Heterodimers bHLH & nonbasic HLH nonbasic proteins block DNA binding binding • ie. MyoD/MyoD homodimer MyoD/MyoD homodimer ---> active active • MyoD/Id heterodimer ---> MyoD/Id heterodimer 10 inactive inactive CLASSES OF HLH PROTEINS CLASSES OF HLH PROTEINS • bHLH proteins: E12 & E47 (Ig enhancer-binding bHLH factors); MyoD, myogenin, & Myf-5 (myogenesis/muscle formation); Myc proto-oncogene (growth reg); da & AC-S (CNS development in Drosophila) Drosophila • Class A: ubiquitously expressed - E12/E47 & da • Class B: tissue-specific - MyoD & AC-S • Combinatorial associations between HLH proteins Combinatorial enable complex regulations ie. various combinations of ie various MyoD/E12/E47/Id regulate muscle cell formation MyoD/E12/E47/Id 11 TRANSCRIPTION FACTOR FAMILIES: HELIX­LOOP­HELIX (HLH) MOTIFS HELIX­ -dimers of bHLH proteins vary in their ability to bind DNA and dimer formation introduces a degree of regulation eg. E12/E47 heterodimer binds DNA strongly but E12 homodimer binds poorly -in Drosophila, the gene emc is involved in establishing pattern of adult sensory organs, and functions by repressing activity of genes such as da (daughterless) and achaete-scute complex (AC-S) 12 Lewin Genes VII 2000 Oxford University Press TRANSCRIPTION FACTOR FAMILIES: HELIX­LOOP­HELIX (HLH) MOTIFS HELIX­ -if da and AC-S not suppressed too many cells a...
View Full Document

This note was uploaded on 03/26/2014 for the course MBB 321 taught by Professor Davidson during the Spring '11 term at Simon Fraser.

Ask a homework question - tutors are online