MCB 2400 Lecture 5: Week 5 Regulation of Gene Expression
5 Nov 2018
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Week 5: Regulation of Gene Expression Part 1
Structure of Hemoglobin:
● tetramer : consists of 4 polypeptide chains
● Adult
○ HbA
○ 2 alpha
○ 2 beta
● Fetal
○ Higher O2 affinity
■ HbF
● 2 alpha
● 2 gamma
● Sickle cell anemia
○ Reactivation of fetal form could potentially solve or decrease the problem by
replacing beta chains with gamma → increase O2 affinity
○ Mutation in the beta globin causes sickle cell anemia
● Transcription regulation
○ Binding of transcription factors to regulatory elements
■ Vitamin D response element (VDRE): ligand-dependent transcription
factor;
● Vitamin D binds to VRD → carry message into nucleus and
activate transcription of target genes (genes that are responsive to
Vitamin D) ; genes with VDRE
● Vitamin D regulates expression of more than 900 genes
○ Altering gene accessibility through chromatin modifications
● DNA is packaged into nucleosomes, nucleosomes condense into
chromatin → chromosome
● Nucleosome core has 8 histone proteins
● Changes in chromatin that affect gene expression
○ Chromatin remodeling
■ Reposition nucleosome to provide easier access to DNA
sequence
■
○ Histone modification
■ Histone core structure
● 8 histones in the core to form a nucleosome
● There are 4 different proteins
● End terminal tails stick out of the nucleosome that
allow for post translational changes to allow DNA to
change its position on the histones
○ Acetylation
Document Summary
Week 5: regulation of gene expression part 1. Tetramer : consists of 4 polypeptide chains. Reactivation of fetal form could potentially solve or decrease the problem by replacing beta chains with gamma increase o2 affinity. Mutation in the beta globin causes sickle cell anemia. Binding of transcription factors to regulatory elements. Vitamin d response element (vdre): ligand-dependent transcription factor; Vitamin d binds to vrd carry message into nucleus and activate transcription of target genes (genes that are responsive to. Vitamin d regulates expression of more than 900 genes. Dna is packaged into nucleosomes, nucleosomes condense into chromatin chromosome. Changes in chromatin that affect gene expression. Reposition nucleosome to provide easier access to dna sequence. 8 histones in the core to form a nucleosome. End terminal tails stick out of the nucleosome that allow for post translational changes to allow dna to change its position on the histones.
