Orthomyxoviridae

Front 1

Orthomyxoviridae classification

Back 1

(-) sense RNA
segmented genome
must enter nucleus
requires host functions in nucleus
enveloped

Front 2

"myxa"
"ortho"

Back 2

mucous
standard/true

Front 3

Orthomyxoviridae generates _____, and has a ______infection.

Back 3

Lots of mucous
lytic

Front 4

Influenza produces fever lasting _______, and symptoms lasting ________.

Back 4

4 - 5 days
3 weeks

Front 5

Influenza "H" designation

Back 5

hemagglutanin - antireceptor
allows for centers of infection
More H than N

Front 6

Influenza "N" designation

Back 6

neuraminidase
More H than N

Front 7

Thogotovirus

Back 7

helical RNP's

Front 8

Influenza _ has greatest disease impact

Back 8

A

Front 9

Influenza M2

Back 9

viroporin - ion channel- necessary for entry

Front 10

Influenza M1

Back 10

Helical RNP's coated with M1

Front 11

RNP's associate with

Back 11

multisubunit polymer PB1, PB2, PA holoenzyme

Front 12

Phospholipid bilayer sensitive to

Back 12

non ionic and lipid solvents

Front 13

Influenza NP

Back 13

Nucleoprotein

Front 14

HA is

Back 14

cleaved into HA1 and HA2

Front 15

HA 1

Back 15

binds the receptor

Front 16

Influenza NS1

Back 16

inhibits host RNA splicing and polyadenlyation

Front 17

Influenza NEP

Back 17

is a viral adaptor to help export unspliced viral mRNAs from nucleus to cytoplasm

Front 18

Influenza segments 1 - 6 encode ______RNAs, where Influenza segment 7 & 8 encode ______RNAs

Back 18

one each

multiple

Front 19

ds viral influenza RNA

Back 19

inhibits interfuron
shuts off protein syn

Front 20

Influenza adsorption depends on

Back 20

cell receptors containing neuraminic acid

Front 21

Mucoproteins

Back 21

have neuraminic acid-abundant in respiratory tract

Front 22

HA

Back 22

Antireceptor - protrudes as globular molecule from surfaces of flu virions

Front 23

Adsorptive endocytosis needs

Back 23

low pH for uncoating

Front 24

low pH during adsorptive endocytosis causes

Back 24

major rearrangement of HA2 portion allowing extension toward cell membrane from envelope

Front 25

Receptor/antireceptor carry out

Back 25

docking

Front 26

M2 ion channel

Back 26

allows penetration of protons from endosome into core of virus

Front 27

M1 protein must be released from ______ before ______occurs

Back 27

RNPs
uncoating

Front 28

Partial uncoating

Back 28

release of M1 but not NP from viral RNA

Front 29

Influenza entry requires 2 steps

Back 29

1)adsorptive endocytosis-low pH
2)activation of M2 ion channel to allow release of M1

Front 30

Amantidine

Back 30

ion channel blocker
prevents uncoating of M1
side effects caused by other ion channel blocking

Front 31

Amantidine resistance from

Back 31

mutants of M2 - keeps ion channel open

Front 32

RNPs have proteins with____________signals

Back 32

nuclear localization

Front 33

NA

Back 33

neuraminidase
envelope protein that cleaves neuraminic acid

Front 34

NA allows spread of virus by

Back 34

by preventing released virus from staying attached to viral producing cells

Front 35

NA facilitiates spread by

Back 35

cleaving neuraminic acid on mucoproteins that are abundant in the respiratory tract

Front 36

Influenza replication:
RNP's move into ______
and stay attached to ______

Back 36

nucleus
RNA pol, PA, PB PB2

Front 37

PA

Back 37

protein acidic

Front 38

PB

Back 38

protein basic
PB1 -protein basic 1
PB2 protein basic 2

Front 39

Actinomycin inhibits

Back 39

DNA dependent RNA polymerase

Front 40

Influenza is inhibited by actinomycin suggesting a

Back 40

DNA dependent event - cap snatching

Front 41

PB1 cleaves

Back 41

cap from nascent cellular mRNA 10 - 13 nucleotides downstream from cap

Front 42

PB2 binds

Back 42

binds cap of cell mRNA

Front 43

PB1 polymerizes

Back 43

RNA cynthesis using cell (cap) RNA as primer

Front 44

PA has ______ role

Back 44

structural role in polymerization, assembly, and elongation of viral mRNA

Front 45

Influenza mRNA gain poly A tail at 3' end by

Back 45

reiterative copying

Front 46

Orthomyxo mRNAs are/are not exact copies of viral genome

Back 46

are not
5' end snatched
3' end poly A

Front 47

Influenza polymerase associates with cell

Back 47

RNA pol II

Front 48

Flu needs

Back 48

m7G mRNA that has A or G 10 - 13 bases dowstream of cap

Front 49

Flu replication prerequiste events

Back 49

Pol bind viral segment
PB 2 binds cap on cell mRNA
Then PB1 activates cleavage event

Front 50

Each segment of flu mRNA has ______ sequence ______ so PA, PB1, PB2 can

Back 50

same sequence at 3' end
recognize them

Front 51

Influenza PB1 is a

Back 51

polymerase

Front 52

synthesis of flu proteins requires

Back 52

full length mRNA synthesis
continuous supply of NP protein for encapsidation

Front 53

Influenza segments 7 and 8 require

Back 53

splicing

Front 54

Most abundant proteins (M1 and NS1 are translated from

Back 54

unspliced mRNA

Front 55

advantage of 2 proteins from 1 unspliced mRNA is

Back 55

regulation of ratio of those 2 proteins

Front 56

During switch from mRNA polymerization to antigenomic

Back 56

polymerase composistion changes

Front 57

PB2 binding cap is ________ in replcation

Back 57

unneccesary

Front 58

Role of PA is

Back 58

critical for replication to begin

Front 59

Genome and antigenome remain associated with

Back 59

NP during replication

Front 60

Antigenome is an

Back 60

exact copy of genomic - no 5' cap or poly a tail

Front 61

secondary transcription

Back 61

transcription off of newly transcribed- amplifies amount of mRNA available for translation

Front 62

NS1

Back 62

accumulates late in IC
promotes ribosome/vRNA assoc
interferes with host mRNA splicing and poly adenylation

Front 63

NS1 also shuts off cell

Back 63

host protein synthesis

Front 64

NS2

Back 64

nuclear export protein

Front 65

Host cell mRNA splicing is coupled with

Back 65

export from nucleus

Front 66

Cleavage of HA occurs by

Back 66

cell enzyme

Front 67

Ability of HA to be cleaved by ubiquitous enzymes allows

Back 67

influenza to extend its tissue range

Front 68

NA must be

Back 68

packaged to allw spread of virus

Front 69

NA allows

Back 69

release of virus from cell that produced it

Front 70

packaging requires incorporation

Back 70

of all 8 segments

Front 71

Random incorporation model

Back 71

more than 8 segments are packaged

Front 72

Selective model

Back 72

Presence of PA and Pol help to slect all 8 segments for each particle

Front 73

Cleavage of _______ of _________ is key to infectivity

Back 73

precursor for HA

Front 74

HA1 and HA2 ________ is required to allow the formation of an ____________ particle

Back 74

cleavage
infectious

Front 75

Influenza infection leads to a _________immune response

Back 75

strong immune response - flooding of blood and lymph into the lungs

Front 76

Antigenic drift

Back 76

Natural mutant selection in infected particle-mistakes by pol

Front 77

61 % difference in HA1 and HA2 is _____ _____ ____ _____ for just __________mistakes

Back 77

too big a difference
polymerase

Front 78

Antigenic shifts

Back 78

reassortments of HA or N or both

Front 79

epidemic

Back 79

increase in frequency or severity of disease over that in normal pop

Front 80

Pandemic

Back 80

world wide increase in frequency or severity of disease

Front 81

Amantidine/rimantidine

Back 81

drug that blocks the M2 channel. Also causes premature triggering of fusion peptide of HA2
can cause seizures/dizziness

Front 82

Tamiflu/Ralenza

Back 82

neuraminidase inhibitor
bloacks active site for neuramic acid
limited efficacy in late infection

Front 83

Potential target of influenza virus

Back 83

cap snatching