Roni's lecture Flashcards
What are transcription factors?
These are proteins involved in converting or transcribing DNA to RNA.
How is DNA, RNA and Protein synthesized?
DNA is synthesized via DNA replication
RNA is synthesized via Transcription
Protein is synthesized via Translation
What does transcription and translation work?
Transcription uses RNA polymerase and transcription factors
Translation converts DNA to RNA to a Protein
What does RNA polymerase 1 do?
It transcribes ribosomal RNAs which are essential for translation.
What does RNA polymerase 2 do?
It transcribes the majority of eukaryotic genes for example mRNA to a protein
What does RNA polymerase 3 do?
It transcribes a variety of RNAs such as 5s pre-rRNA, tRNA and snRNA.
What are transcription factors?
They are proteins that bind to DNA and help recruit appropriate polymerase which helps control the rate of transcription of genetic material from DNA to RNA.
How do transcription factors work?
They bind to DNA regulatory sequences and help recruit cofactors such as activators and coactivators.
What are ACTIVATORS?
They are regulatory proteins bind to DNA at distant sites which is known as enhances.
What are COACTIVATORS?
These are transcription factors that transmit signals from activator proteins to general factors.
What are general factors and what do they do?
They are transcription factors that places RNA polymerase at the start of coding sequence and releases them to initiate transcription.
What are the examples of steriods?
Sex hormones and corticosteriods
What is the primary function of the estrogen?
It helps for the development of secondary female characteristics such as the breast and menstrual cycle.
What are the effects of estrogen on bone?
It provides vitamin D and calcium
What are the effects of estrogen on the liver?
It increases hepatic production of binding protein
It helps increase good cholesterol HDL
It helps decrease bad cholesterol LDL
What are the effects of estrogen on the heart?
Helps prevent atherosclerosis
What are the effects on estrogen on the brain?
It protects against nerve damage
It delays memory loss
helps nerve growth
what are the two types of estrogen receptors and give examples of each?
Alpha for example breast cancer cells, endometrium , ovarian stoma cells
Beta for example brain, heart, kidney and lung
The two estrogen receptors are located on the same chromosome.TRUE OR FALSE?
FALSE
ER(a) and ER(b) have different tissue distributions and transcriptional regulatory effects on target gene. TRUE OR FALSE?
TRUE
Estrogen enters all cells? TRUE OR FALSE
TRUE
What are the harmful effects of estrogen on breast and uterus?
Increases risk of cancer in both
How does cancer arise?
It arises from DNA mutations in cells
How do mutations occur?
Can be heredity
Can be due to spontaneous errors in DNA replication
Can be due to chemicals/radiation
What does SERMs stand for?
Selective estrogen receptor modulators
Certain antiestrogen drugs are not pure antagonists but rather mixed agonist/antagonist.TRUE OR FALSE?
TRUE
The ability of the ER to interact with other transcriptional cofactors depends on the structure of the ligand that is bound to the receptor. TRUE OR FALSE?
TRUE
How do ER antagonists in breast tissue work?
They inhibit the estrogen dependent growth of breast cancer cells
How do partial ER work in endometrium and bone?
They stimulate growth
How does tamoxifen work?
It inhibits breast cell proliferation but stimulates cell growth in the endometrium
What are the positives and negative aspects of tamoxifen when used as an anti -breast cancer drug?
It reduces risk of cancer It increases blood clots
It decreases LDL It increases chances of
uterine cancer
It strengthens bone
What is considered to be an ideal SERMs?
It decreases LDL decreases blood clots strengthens bone reduces chances of breast cancer and uterine cancer it reduces hot flashes
What are the positive aspects of Raloxifene?
Reduces chances of breast and uterine cancer
strengthens bone
Causes fewer blood clots than tamoxifen
reduces LDL and increases HDL
What are the negative aspects of Raloxifene?
causes hot flashes
causes leg cramps
causes birth defects (teratogenic)
causes blood clots
Describe the antagonist activity of Raloxifene?
It reduces risk of breast and endometrium cancer
What are the agonist effects of Raloxifene?
It decreases bone resorption and delays the progression of bone loss so can therefore be used to treat osteoporosis.
What is clomifene and Where is it located?
It is a ER in the hypothalamus and the anterior pituitary
How does clomifene act as an antagonist?
It results in a relief of negative feedback inhibition is imposed by endogenous estrogen, it increases GnRH which causes ovulation.
How does clomifene act as a partial ER agonist?
In the ovaries it acts causes ovulation and is used to treat infertility
