Gene Structure Flashcards Preview

Foundations Test 1 > Gene Structure > Flashcards

Flashcards in Gene Structure Deck (27)
Loading flashcards...
1

Example of closely related gene cluster and how they are formed

B-globin
Duplication and then divergence

2

Each gene of B-globin cluster has

Own promoter

3

SNP

Single nucleotide polymorphisms
Most of genetic variation

4

INDELS

INsertions and DELetions

5

Microsatellites

SSR repeats of 2-5 BP
Also called variable tandem number repeats

6

Interspersed repeat sequences

SINES (Short interspersed repeated elements)
LINES (long interspersed repeated elements)

7

CNV

Copy number vairations
Direct repeats at a locus
***Account for differences in amount of gene produced

8

Microsatellite disease

HNPCC (hereditary non-polypsis colorectal cancer)

9

HNPCC caused by

Changes in microsatellite repeat length (MSI)
Microsatellite instability

10

PCR will show what in MSI?

Extra products in tumor tissue vs normal

11

Colon cancer signs

Constipiate
Diarrhea
Blood in stools
Narrow stools
unexplained anemia
Abdominal pain
Unexplained weight loss
Weakness and fatigue

12

Sporadic cancer

Blood - inherited CNVs
Tumor - Inherited and tumor specific CNVs

13

Inherited cancer

Blood - inherited CNVs
Blood - Inherited and acquired CNVs
Tumor - inherited, acquired, and tumor specific CNVs

14

c-MYC is example of

proto-oncogene

15

In Burkitt's lymphoma, c-MYC moves next to _____

H chain enhancer on chromosome 14 near IGH

16

snRNPs

small nuclear ribonucleoproteins that perform splicing reactions

17

Consensus sequences in precursor mRNA for splicing

5' splice (GU)
3' splice (AG)
Site just 5' to the 3' site called the branch site

18

Steps of splicing

1) snRNPs associate with splice site sequences to form splicesome
2) 2' OH of branch site A nucleotide attack phosphodiester bond at junction of 5' splice site...cleaves to form 3' OH at 5' end
3) 3' OH at 5' splice site attack and covalently bonds to 3' splice site...this is joining of splice site and intron released

19

Alternative splicing means

Can get multiple functional proteins from 1 mRNA

20

FGFR-2 splicing

Can result in different affiinities for different ligands based on alternative splicing

21

Alternative splicing of Bcl-x

BCLx- short - pro-apoptotic
BCLx-long - anti-apoptotic

22

Tissue dependent alternative splicing

mRNA making calcitonin and CGRP are from same
In thyroid - makes calcitonin
In brain - makes CGRP

23

Cryptic splice site

Sequence with some similariyt to a splice site and can be used at a low rate by splicing machinery or a high rate if mutated

24

Altered globin mRNA splicing can lead to

Thalassemias - less functional hemoglobin

25

Intron 1 cause of B thalaseemia

Site within intron 1 becomes better 3' acceptor than normal. 90% of mRNA made is wrong...RNA will be decayed

Only 10% is normal

26

Spinal Muscular Atrophy

Mutation in SMN2 gene that causes exon 7 to be skipped...leads to unstable SMN2 protein
Still have SMN1 protein but not enough

27

Therapeutics for thalassemias and other aberrant splicing diseases

Antisense oligonucleotides
Base-pair to mRNA sequences in mRNA representing new cryptic sites...this supresses their use