Chapter 5: Regulation of Eukaryotic Gene Expression

Question 1

Other than general transcription factors leading to basal trascription, what is name of a place for specific transcription factors to pump more gene expression?

Answer 1

Enhancer

Question 2

What is the difference between General transcription factors and Specific transcription factors?

Answer 2

• General transcription factors must bind to the promotor to allow RNA polymerase II to initiate trascription.(ex. TATA box with TFIID, CAAT box with NF-1)
• Specific transcription factors bind to enhancer regions.

Question 3

What is Zellweger syndrome and what causes this disease. Thus, symptoms.

Answer 3

• deficiency of peroxisomes which causes an accumulation of very long chain fatty acids
• Mutation in any one of several genes involved in peroxisome biogenesis.
  Sx) enlarged liver, high blood levels of Cu and Fe, and vision problems(peroxisome is usually in the liver, they are involved in metal homeostasis, they involve in synthesis of plasmogens, used in myelin sheath of retinal nerve)
  Sx in infants) failure to grow, intellectual disability, abnormal muscle tone, usually die in first year

Question 4

A 50-year-old man sees his physician for increasingly frequent episodes of acute pain in his upper abdomen and back after meals. The physician orders fasting blood tests and the results are notable for mild hypocalcemia(8.4mg/dL; normal 8.9-10.3 mg/dL) and hypertriglyceridemia(500mg/dL;normal<200mg/mL) with increased VLDL. Total cholesterol(170mg/dL;normal<200ml/dL), LDL cholesterol(100mg/dL;normal<130mg/dL), and HDL(34mg/dL;normal 34-86mg/dL) are within normal ranges.
Dx) & Tx)?

Answer 4

Dx) Hypertriglyceridemia
- Peroxisomes accomplish beta-oxidation of LDL & VLDL.
Tx) Gemifibrozil
- hypolipidemic drug that is prescribed to treat certain types of hyperlipoproteinemia

Question 5

Describe two factors leading to Gluconeogenesis

Answer 5

1. Cortisol
   - diffuse into hepatocyte binds through the zinc fingers to the glucocorticoid response element (GRE)associated with PEPCK gene(phosphoenolpyruvate carboxykinase; rate limiting step for gluconeogenesis)
2. Glucagon
   - cAMP concentration increases
   - protein kinase A becomes active which activates CREB(cAMP response element binding protein) which binds to CRE associated with PEPCK

Question 6

Reason of Klein-Waardenburg syndrome, Sx)

Answer 6

During development in Utero, Homeodomain proteins are important for controlling proper time of gene expression. They are encoded by genes like HOX, PAX. Mutation of PAX gene causes Klein-Waardenburg syndrome.

Sx) Distopia canthorum(lateral displacement of the inner corner of the eye)
Pigmentary abnormalities
Congenital deafness
Limb abnormalities