| Question |
Answer |
| Rifampicin |
interferes with initiation of transcription by blocking the passage channel fo RNA/DNA hybrid, prok only |
| Actinomycin |
inserts itself btwn base pairs (DNA can't be a template for RNA pol) both prok and eukaryotes |
| streptolydigin |
binds to RNA pol, prevents phosphodiester bond formation (prok) |
| α-amanitin |
strongly inhibits RNA polymerase II, weakly inhibits RNA pol III (euk) |
| streptomycin |
inhibits initiation, misreading of mRNA (prok) |
| tetracycline |
binds to 30s, inhibits binding of aminoacyl-tRNA (prok) |
| chloramphenicol |
inhibits peptidle transferase at 50s (prok) |
| cyclohexamide |
inhibits peptidyl transferase activity in 60s (euk) |
| Erythromycin |
binds to 50s subunit and inhibits translocation |
| Puromycin |
premature chain termination, acts as an analog of aminoacyl-tRNA (prok & euk) |
| Cyclin D |
CDK 6&4 get through G1 |
| Cyclin E |
CDK 2 G1--> S |
| Cyclin A |
S-->G2-->M, regulated by APC |
| Cyclin B |
CDK1 through M, regulated by APC |
| Retinoblastoma |
Rb is a tumor suppressor gene, usually binds & inactivates E2F, with growth signals Rb is phosphorylated and releases E2F (transcription factor) |
| p53 |
transcription factor, ordinarily synthesized and degraded, if it hangs out to long it moves into the nucleus and turns on transcription of p21 (CDK-inhibitor) |
| Li_Fraumeni Syndrome |
inherited p53 defect |
| autosomal dominant |
1. no skipping of generations
2. males and females are equally likely to be affected
3. normal siblings of affected individuals do NOT pass it on
4. usually a structural protein not an enzyme |
| Marfan Syndrome |
Autosomal dominant (variable expressivity), mutation in the FBN1 gene, chrom 15 - encodes for fibrillin-1, skeletal abnormalities |
| Huntington |
Autosomal dominance (late onset), CAG repeats in the coding section (encoded bc of strand slippage during replication) |
| myotonic dystrophy |
autosomal dominant, delayed expression in NON-translated region, slowly progressive muscle weakness and myotonia |
| genetic anticipation |
tendency for the severity of the disease to increase and the age of onset to decrease |
| fragile x |
X-linked dominant increased CGG repeats, FMR1 not expressed, no protein made, since females carry 2 Xs tends to be milder |
| neurofibromatosis type 1 |
cafe au lait spots, protein is neurofibromin which causes a loss of growth supressors, autosomal dominant inheritance (high new mutation rate) |
| achondroplasia |
autosomal dominant, high recurrent mutation, short stature, mutation in the fibroblast growth factor receptor gene 3 (severely shortened bones) |
| Potter's syndrome |
autosomal dominant, incomplete penetrance |
| Autosomal recessive |
1. equal male & female
2. sibling recurrence rate is 1/4
3. characteristically found in siblings, not parents
4. parents may be related
5. may be an isolated event in small sibships |
| X-linked recessive |
never pass father to son
affected females MUST have affected fathers
typically passed from affected grandfather to 1/2 of grandsons |
| X-linked dominan |
never pass father to son
all daughters of affected parents are affected, all sons of affected male and unaffected female are normal
affected females x normal male = 1/2 affected sons
male more seriously affected than females |
| Patau |
trisomy 13, usually die within 3 months |
| edwards syndrome |
trisomy 18, distinct facial features, 80% of those affected are females, |
| klinefelter |
XXY low levels of testosterone |
| turner |
XO, underdeveloped female secondary sex characteristics, webbed neck |
| williams syndrome |
deletion of the q arm of chrom 7 (including elastin gene), broad forehead, short nose, widely spaced teeth |
| cri du chat |
deletion of the short arm of chrom 5, 80% of time comes from father's sperm,abnormal larynx development = mewing (becomes normal w/i few weeks), |
| imprinting |
reversible form of inactivation, acts through methylation, only occurs on 9 chrom |
| prader-willi |
small deletion on the short arm of chrom 15 from father. hypotonia, difficulty feeding, insatiable appetite, small hands and feet, hypogonadism |
| angelman |
small deletion on short arm of chrom 15 from mother, severe mental retardation, nonverbal, balence disorder |
| osteogenesis imperfecta |
mosaicism, type 1 collagen disorder, easy fractures of the bone, autosomal dominant |
| methotrexate and aminopterin |
inhibit thymidylate synthase (no dTTP) |
| fluorouracil |
inhibits dihydrofolate reductase (do dTTP) |
| HGPRT |
deficiency --> Lesch Nyan, X-linked recessive |
| Adenosine deaminase deficiency |
used in purine salvage pathway, causes SCID, ATP and dATP accumulate --> imbalnce of nucleotide pool, prevents DNA syn |
| glutamine PRPP amidotransferase |
purine synthesis, removes pyrophosphate from PRPP leavind a phosphoribosyl amine |
| Xanthylate synthase |
uses NAD and H2O to form a carbonyk, can be inhibited by GMP |
| allopurinal |
suicide inhibitor of xanthine OXIDASE, enzyme can't degrade purines to urate |
| carbamoyl phosphate synthase |
pyrimidine synthesis, NOT from urea cycle, inhibited by UTP, activated by PRPP |
| ribonucleotide reductase |
removes 2'OH, so they can be incorporate into DNA, regulated to keep the dNTPs in balence |
| campothecin and doxorubicin |
type 1&2 topoisomerase inhibitors, stabilize the DNA-topoisomerase complex, DNA makes cut and the drug blocks the reattachment |
| cohesins |
hold chromosomes together, regulated by APC (through securin and separase) |
| T-loops |
hides dsDNA from DNA repair machinery, free of nucleosomes, stabilized by TRF1 proteins |
| RNA syn |
does NOT require a promoter, initiation is TATA region, termination is GC rich (forms hairpin), can also have rho factor (ATPase and a helicase, binds to Crich, G poor region and pulls it away from the RNA pol and DNA template) |
| RNA trasncription |
a DAB of F brings RNAPOL, EH? |
| spliceosom |
snRNPs and pre-mRNA |
| B-thalassemia |
abnormal splicing of B-globin |
| amino-acyl tRNA stnthetase |
requires ATP |
| ran |
signal peptide receptor in nucleus and cytoplasm, serves in both nuclear import and export, |
| NF-AT |
transcription factor mediated by nuclear import/export, wehn it is stimulated calcinurin moves to the nucleus and stimulates trascription, in low calcium environment calcineurin falls off and the NF-AT is kicked out of the cell |
| cholera |
colonize the small intestine and produce mono-ADP-ribotransferase, modifies the G-protein involved in walter and salt balence. G-protein cannot release GTP so Adenylyl cyclase is active --> inc cAMP --> intestinal cells secrete water and salts |
| Pertussis |
whooping cough, colonize the lungs and add ADP-ribose ot G-protein resulting in inc mucus secretion |
| Diphtheria |
infect nasopharynx/skin, toxin is endocytosed after binding to epidermal growth factor receptor --> acidified in endosome --> ribosylation of EF2 (blocks protein syn) |
| Ricin |
heterodimeric ribosome-inhibiting proteinm doens't use NAD+ instead cleaves A and stops protein syn |
| somatic cell hybrids |
use sendai virus to fuse 2 cells and nuclei from different species. can't be used for disease genes |
| RFLP |
markers to certain locations on different chromosomes, can indicate whether crossing-over has occurred btwn the marker and the disease gene (show you how close together the 2 are) |
| Beckswith Wiedemann Syndrome |
chrom 11 - imprinted in father, maternal deletion = syndrome, paternal deletion = no effect |
| CGH comparative genomic hybridization |
detects global gains and losses by compaing sa,ple DNA to the normal human chrom, can detect anueploidy or gene amplificaion in tumors, will not detect balenced rearrangements |
| GPCRs |
largest family of cell surface receptors, 7transmembrane domains, extracellular domain binds ligand, can be inactivated by receptor inactivation, receptor internalization or receptor downregulation |
| ATP used per peptide bond in protein synthesis |
4 |
| Neurofibromatosis II |
mutation on tumor supressor gene, chrom 22, Bilateral acoustic neuroma (CN VIII), Juvenile cateracts
|
| Rett's |
MECP2 genes>> form synapses between nerve cells, unclear,
X-linked, fatal in males, hand-wringing |
| Beckwith- Wiedemann |
Macrosomia: large body
Macroglossi: large tongue
Enlargement of internal organs
maternally imprinted
Wilm’s tumor and embryonal tumors
omphalocele
|
| Xeroderma pigmentosa |
inability to repair thymine dimers |
| Ataxia telangectasia |
defect in ATM protein>> protein kinase activated by double strand breaks |
| Wilm’s tumor |
defect in the imprinting of the insulin like growth factor 2 gene>> both maternal and paternal expression
Symptoms:
Childhood tumor of the kidney
|
| karyotyping with light microscopy |
G-banding |
Ch.18 LTI-MA 509
