Regulatory proteins or ribonucleic acids {transcription factor}| bind before and after genes. Transcription factors and DNA regions differ for different genes. Typically, genes have several regions, for transcription-factor sets. Eukaryote DNA has transcription-factor recognition sites at gene 5' and 3' ends.
Fos
C-fos genes make Fos protein transcription factors.
TATAA
TATAA sites are at 5' ends, just before mRNA transcription-start sites.
GC box
GC boxes are at 5' ends, just before mRNA transcription-start sites.
CCAAT
CCAAT sites are at 5' ends, just before mRNA transcription-start sites.
mRNA enhancer
50-base to 150-base mRNA-enhancer sites can be at 3' ends, 5' ends, or anywhere. They have redundant regions. They react to signal molecules, heat, metal ions, growth factors, or hormones. They contain regions that suppress other-cell-type transcription.
AAUAAA
AAUAAA sites at 3' ends act as signals to cut mRNA 10 to 30 bases away and then add polyA tails.
zinc finger
RNA-polymerase-III 50-base internal-control regions have two regions that bind zinc.
transcription factors: classes
Eukaryotes have transcription-factor classes that bind to DNA-regulatory-region sites: RNA polymerase II promoter, homeodomain, zinc finger, leucine zipper, and helix-loop-helix.
transcription factors: RNA polymerase II promoters
Eukaryotes have transcription factors that bind to RNA polymerase II promoters. Eukaryote promoters have DNA-binding sites and transcriptional-activation sites. Transcription factors help RNA polymerase bind to promoters or change reaction rates. TFIID binds to TATAA sites. TFIIA binds before TATAA sites. TFIIB works with RNA polymerase II. TFIIE binds after RNA polymerase II sites.
transcription factors: homeodomain binding proteins
Homeodomain binding proteins have one helix lying in DNA major groove and another helix lying across DNA to contact other proteins. Fruitfly homeotic genes control body development and contain 180-base homeobox control regions that have helix-turn-helix homeodomain found in most development genes. Vertebrate Hox genes are similar.
400 million years ago, Hox Ubx regulatory-gene mutations caused sea-dwelling arthropods with limbs on all body segments to evolve into terrestrial six-legged insects. Ubx regulates many other genes to prevent fruitfly (Drosophila) thorax-limb development, allow some brine-shrimp (Artemia) thorax-limb development, and allow other-crustacean thorax limbs.
transcription factors: zinc finger
Zinc-finger binding proteins {Kruppel protein} have repeated cysteines and histidines involved with zinc, as in SV40 early-gene GC-box Sp1, steroid-receptor proteins, and gap-gene proteins.
transcription factors: leucine zipper
Leucine-zipper binding proteins, such as FOS oncogene and JUN oncogene proteins, have four or five leucines, seven amino acids apart and just after arginine and lysine regions, that make dimers that bind to DNA.
transcription factors: helix-loop-helix
Helix-loop-helix binding proteins have regions, with arginine and lysine, that bind to DNA and make dimers, as in MyoD-gene and Myc-gene proteins.
Biological Sciences>Genetics>DNA Regulation>Protein
4-Genetics-DNA Regulation-Protein
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Date Modified: 2022.0224