Gene Regulation In Eukaryotes

Genes that are always on such as actin and other genes that make up cytoskeleton and genes that make enzymes that carry out glycolysis.

Proteins that clear metals are induced only when metals are present in the body.

All cells have the same genes in them, but different tissues turn on only a certain subset of genes. This is caused by epigenetic factors.

Globin genes. Gamma-Hb is seen in higher amounts in fetus because it has a higher affinity for oxygen than beta. This gradient is needed to take oxygen out of the mother's blood. Beta- Hb increases after birth because the baby can no respirate.

Changes in chromosome shape.

Chromatin configuration that changes to make promoter region more or less accessible to transcription factors.

Regulatory sequences interact with transcriptional activators/inhibitors.

Alternative cleavage and splicing of pre-mRNA

Poly-A tail and interfering RNAs regulate RNA longevity.

5' and 3' UTRs and interfering RNAs regulate the rate of translation

1. Hormone binds to extracellular domain of receptor protein

2. Receptor protein's intracellular domain initiates biochemical cascade (involving phosphorylation of proteins inside cell)

3. Biochemical cascade alters transcription factor, allowing it to enter nucleus and activate/inhibit genes.

An enzyme that cuts DNA into each pyrimidine nucleotide (C and T).

1. Methylation of histones (often on lysines)

2. Acetylation of histone proteins (often on lysines)

3. Methylation of DNA (often the Cs in CG islands in promoter region)

Can activate OR repress gene activity. It enhances transcription in H3K4me3 by adding three methylgroups to histone 3 (lysine number 4). K stands for lysine.

Complexes of transcription factors and other proteins that can move nucleosomes around, exposing promoter sites so transcription factors can bind them. Can slide nucleosome down DNA to expose promoter, or change conformation of DNA and/or nucleosome to expose promoter.

Usually inhibits transcription of genes in that region. Most commonly known example is methylation of cytosines in the promoter region of genes. This prevents transcription from occuring. 2-7% of cytosines are methylated in eukaryotes. This however, does not happen in drosophilla or yeast.

This gene has a trinucleotide repeat (CGG) in the promoter region with a variable length. Too many repeats (over 200) causes increased methylation of the gene, deacetylation of histone proteains, inhibition of FMR1, which leads to Fragile X-syndrome.

-X that gets inactivated produces XIST which is an RNA. This RNA coats the chromosome, supercondensing it and fostering methylation of promoter region.

-The other X protects itself from XIST RNA by producing TSIX RNA which is complementary to XIST RNA. TSIX RNA binds to XIST RNA and prevents it from inactivating the second X.

Child will have either two or zero working copies of its impointed genes instead of one working copy he/she should have.

X-linked gene that silences gene expression by recruiting histone deacetylase activity, reinforcing a represive chromatin state.

Have domain that bind to methylated DNA and a domain that has histone deacetylase activity.

Caused by loss of function mutation of MeCP2. Normal development for 6 months then regression of cognitive capabilities and causes microcephaly.

Eating royal jelly causes famale to develop into a queen and be able to reproduce because it contains DNA methyltransferase 3 gene (Dnmt3) which changes methylation, and expression of many genes.

If mother has excessively high sugar or fat level, the child that is born will not beable to metabolize more nutriionally balanced food.

heritable changes in gene expression due to epigenetic effects.

In males, upstream 3' splice site is used. In females, Sxl protein causes downstream 3' splice to be used.

upstream 3' splice site in males causes premature stop codon in mRNA and no functional protein is produced and male is produced.

Downstream 3' splice site in females creates a functional protein and female is produced.

Bind to poly-A tail to stabilize the mRNA (because this is where RNAses degrade mRNA). When mRNA's poly-A tale is too short, the binding proteins can not bind and mRNA will degrade quickly.

They rely on having a base sequence that is complementary to some portion of the mRNA sequence or gene itself so that it can bind.

siRNAs are double stranded RNAs that are taken up by cells.

miRNAs are single stranded RNAs that are transcribed from sequences in cell's genome.

p53 is a transcription factor that regulates a number of genes that produce proteins that regulate cell cycle and apoptosis. This dysfunction caused by lincRNA-p21 is frequently involved in cancers.

Tags proteins for degradation