Exam 2 proteins, genes, enzymes, etc Flashcards
1
Q
what are the major roles of folic acid (vitamin B9)
A
- biosynthesis of thymidylate and the purine nucleic acid bases (dna synthesis)
- methylation of homocysteine to produce methionine
2
Q
what does S-adenosyl methionine do?
A
most important carrier of methyl groups
3
Q
what does thalidomide do?
A
- sedative
- alleviates morning sickness over the counter
- teratogen (produces defects in developing fetus)
4
Q
what syndrome is associated with KIT gene
A
piebaldism
5
Q
what syndrome is associated with RET gene?
A
waardenburg syndrome
6
Q
what is HOXA11?
A
a member of the homeobox gene family that is associated with radioulnar synostosis and thrombocytopenia
7
Q
what is hoxa 13
A
member of the homeobox gene family and is associated with hand foot genital syndrome
8
Q
what is hoxd13
A
member of the homeobox gene family and associated with synpolydactily (webbing and digits duplication)
9
Q
what is IDX1
A
- homeobox gene
- required for pancreas development
- mutations in humans can lead to diabetes type 1
10
Q
what are hox genes usually associated with?
A
HOXA-HOXB clusters with rostral caudal axis establishment
HOXA HOXD clusters with limb development
11
Q
what are PAX genes associated with?
A
9 transcription factors involved in cell fate determination, not in clusters
12
Q
what are the 5 pax genes involved in diseases?
A
pax 2, 3, 6, 8, 9
13
Q
what is the disease caused by pax 6 mutation?
A
aniridia, complete loss of the iris
14
Q
what are FGF’s?
A
fibroblast growth factors
15
Q
how many FGF encoding genes are there
A
23
16
Q
how many FGFR encoding genes are there
A
4
17
Q
what gene is associated with vitamin d resistant rickets
A
FGF23
18
Q
FGFR1, FGFR 2 and 3 mutations lead to what?
A
there are 12 different syndromes they cause, examples are craniosytostoses, achondroplasia, and dwarfism
19
Q
what are the 3 ligands associated with the sonic hedgehog pathway
A
SHH (sonic hedgehog) IHH (indian hedghog)
DHH (desert hedgehog)
20
Q
what are the three general pieces to the sonic hedgehog pathway?
A
shh (ligand) binds to Ptc1 (receptor) and proteins relay signal to Gli3 activator to the nucleus
21
Q
autosomal dominant mutation in what causes holoprosencephaly
A
SHH
22
Q
IHH mutation causes what?
A
brachydactyl (short fingers) type 1
23
Q
what is PAX3 mutation associated with?
A
heterochromism (different eyes), hearing loss and white forelock
24
Q
what is type 2 of waardenburg sydnrome caused by?
A
MITF mutation
25
what is type IV waardenburg and hirschprung disease caused by?
SOX10 and END/EDNRB mutation
26
in what cases of mutations do you get both waardenburg and hirschprung?
1. RET on chromosome 10
2. EDNRB on chromosome 13
3. SOX10 on chromosome 22
27
what are the genes involved with sex determination?
SRY presence means a Y chromosome pops up and male. DAX1 gene means female
28
what is the relationship between leydig cells, testosterone, and male determination?
1. leydig cells make testosterone
2. testosterone stimulates Wolffian duct
3. wolffian duct forms male genitalia
29
what is the relationship between sertoli cells, AMH, and male determination
1. sertoli cells make anti-mullerian hormone (AMH)
2. amh shuts down mullerian duct
3. shut down of mullerian duct
30
what role does androgen play in male determination?
binds to the promoters of male genitalia making genes
31
what would having 1 copy instead of 2 copies of Dax1 gene do?
turner syndrome, failure of ovary development
32
what would having too much dax1 by SRY do
klinefelter syndrome, small testes
33
what happens if SRY interacts with products of SF1, SOX9, and WT1 genes?
makes male gonads, male pseudohermaphroditism
34
what does WT1 mutation do?
causes denys-drash syndrome, renal disease and wilms tumor and 46, XY females
35
what does Sox9 mutation do?
campomelic dysplasia, 46 XY female
36
what does SF1 mutation do?
46 XY female
37
what role does androgen receptor mutations play as it pertains to male pseudohermaphroditism?
produce androgen insensitivity so no male genitalia. SRY is expressed, produce amh so no ovaries. but by default external genitalia is formed by female type but testes stay hidden in abdomen
38
how many chromosomes do mature eggs and sperm cells have?
haploid sets of 23 chromosomes
39
how many chromosomes are in every human cell
46 chromosomes (23 pairs=diploid)
40
what is trisomy 13 associated with
patau syndrome
41
what is trisomy 18
edwards syndrome
42
what is trisomy 21
down syndrome
43
what are 3 parts of the triple test for risk assessing down syndrome prenatally
alpha fetoprotein (AFP) unconjugated estriol and chorionic gonadotropin
44
how exactly does AFP help with testing for down syndrome
its made in the fetal liver and some escapes into the maternal circulation. if the level is lower than in normal pregnancy then its considered a warning sign bc fetuses with down syndrome tend to be a little smaller on average and have smaller placentas
45
what is the APP
amyloid precursor protein, in 21q21, deposition of amyloid plaques of in alzheimers brains
46
GATA1 gene is involved in what?
responsible for megakaryoblastic leukemia, always mutated in down syndromes with cancer but the gene itself is located on chromosome X
47
be able to identify/recall some genes that when overexpressed may have input in down syndrome
-SOD1 -COL6A1 -ETS2 -CAF1A -cystation (beta) synthase (CBS) -DYRK -CRYA1 -IFNAR
48
what is the short stature of turn syndrome caused by and how is it treated
caused by low dose of SHOX gene on the Xh chromosome. treated by growth hormone
49
what is the treatment for no ovarian function in turner syndrome
estrogen-progesterone treatment
50
where does robertsonian translocation only happen in?
only happens with chromosomes 13, 14, 15, 21 and 22 (rDNA carriers)
51
what is c-myc gene
a locus controlling transcription of an immunoglobulin genes
leads to the overproduction of the Myc transcription factor
in lymphocytes and the development of a lymphoma.
52
what is the candidate gene for wolf hirschhorn syndrome deletion
LETM1
53
what are the candidate genes for cri du chat syndrome
telomerase, catenin CCNND2, semaphorin F
54
what is the relevance of elastin gene in williams syndrome
as elastin gene is deleted, children have narrow arteries (vascular stenosis)
55
what gene is associated with jacobsen syndrome
Fli-1 gene
56
what gene is associated and when mutated produces symptoms similar to smith magenis syndrome
RAI1 gene
57
what is signficant of genes between LCR1 and LCR2
most studied,
as 1/ 12 of 22q11 pats
have small deletion LCR1/2
and classical type of the disease
58
what is HIRA
a transcription factor associated with 22q11 that has to do with development of limbs and cranium
59
what is tbx1
transcription factor with 22q11 and has to do with aortic defect and thymus agenesis
60
what is E2F6
a transcription factor associated with 22q11 and has to do with general cell proliferation
61
what is GSCL
transcription factor with 22q11 that has to do with craniofacial development
62
most patients of NBS have what leading to their mutation
homozygous for the founder mutation 657 del5 (NBS1 gene)
63
what is ataxia telangiectasia (ATM) due to
homozygous point mutations in ATM gene
64
60% of women with heterozygous what develop cancer by the age of 70
60% of women with the heterozygous ATM gene mutation develop cancer by the age of 70
65
antibodies to what cause CREST syndrome
antibodies to centromeric proteins
66
what role does telomerase play in cancer
its stringently repressed in normal human somatic tissues but reactivated in cancer
67
mutations in what genes can cause HNPCC
MSH2 and MHL1
68
what are the functions of oncogenes
- accelerators of cell division
- stop apoptosis
- dominantly inherited (one defective allele can predispose the cell to tumor formation)
69
tumor suppressors do what
- inhibitors of cell division
- help for apoptosis
- recessive (Mutation in one allele predispose human to cancer, but do not cause it)
70
what are the growth factors and growth factor receptors for oncogenes?
Growth factors: TGFa, EGF
| Growth factor receptors: EGFR
71
what are the signaling mediators for oncogenes
ras, src, akt
72
what are the transcription factors for oncogenes
myc
73
what are the cell cycle components for oncogenes
cyclin D1
74
how is ras activated
from proto oncogene
1. deletion or point mutation in coding sequence
2. hyperactive protein made in normal amounts
3. ras, colon carcinoma
75
how is egfr activated
from proto oncogene
1. gene amplification
2. normal protein greatly overproduced
3. egfr breast carcinoma
76
how is myc activated
from proto oncogene
1. chromosome rearrangement
2. nearby regulatory dna sequence causes normal protein to be overproduced
3. myc lymphoma
77
how is bcr/abl/cml
from proto oncogene
1. chromosome rearrangement
2. fusion to actively transcribed gene greatly overproduces fusion protein; or fusion protein is hyperactive
3. mcr, abl, cml
78
what are some traits of tumor suppressor genes
If one copy is gone/mutated, second normal allele will function.
If both copies are gone/mutated, cancer can progress (two hit hypothesis).
Replace a single normal copy and cells return to normal (cell fusion assay).
79
what is the function of rb1 gene
it is an inhibitor of a gene regulatory protein. when inhibited by cyclin d1-cdk4 complex then allow e2f to proceed
80
what does e2f do?
when not inhibited by rb1, transcription of target genes that control entry into S phase
81
what are some pro angiogenic factors
VEGF, FGFs, IL-8, prostaglandins
82
what are MMPs
matrix degradation enzymes, promote detachment of tumor cells from neighboring cells
83
what helps promote detachment of tumor cells from neighboring cells
mmps and other proteases
84
what inhibits detachment of tumor cells from neighboring cells
protease inhibitors and intercellular adhesion
molecules
(cadherins, integrins etc
