Regulation Of Eukaryotic Transcription Flashcards
Housekeeping genes
Expressed in all cells
Temporally regulated genes
Expressed at certain times
Tissue - specific genes
Expressed in some types of cells
Response elements
DNA sequences in the promoter needed for the initiation of the activity of the RNA pol
Domains of transcription factors
DNA binding, transactivating, dimerzation, and ligand binding
DNA binding domain
Recognizes DNA response elements
Includes zinc finger domain, helix-turn-helix, helix - loop-helix, and leucine zipper
Transactivating domain
Binds to other components used to regulate genes
Dimerization domain
Acts as a dimer and binds to its partner
Ligand binding domain
Binds to ligand to induce the transcription factor
Steroid hormone receptors
Ligand -dependent transcription factors that function as a dimer, they are classified into homodimers and heterodimers
Why are steroids powerful?
Cus they can turn on sets of genes
Homodimers
Have a palindromic arrangement and bind to the half site TGTTCT
Heterodimers
Arranged in half site direct repeats with rxr, the half site is TGACCT and the number of nucleotides is what determines which receptor binds to it
Covalent modification
Adding a phosphate group to a transcription factor to change its shape
Cell localization
Change the location of a transcription factor to regulate it
Cell sequestration
Binding a transcription factor to other factors to hold on to it and trap it
Ligand binding
Activity of transcription factor is regulated by whether the ligand /hormone is present or not
Packaging of DNA
DNA is wrapped around histones to form nucleosome loops then it is coiled to form a solenoid then radial loops
Epigenetics
Inheritable information that is encoded by modifications of genome and chromatin components, it affects transcriptional regulation
Histone modifications
Alters degree of relaxation or compaction of chromatin
DNA methylation
Adding methyl group to cytosines in promoters to block access to transcription factors
