21. Rhabdovirus/Paramyxovirus

Question 1

4 types of genomes in RNA viruses

Answer 1

1. +RNA
2. -RNA
3. dsRNA
4. ssRNA retroviruses

Question 2

3 properties of -RNA virus

Answer 2

1. genomic RNA is not mRNA
2. genomic RNA is template for mRNA and genomic RNA
3. package RdRP in virion

Question 3

are -RNA viruses non-enveloped or enveloped?

Answer 3

enveloped

Question 4

how do -RNA viruses enter the cell? how do they exit?

Answer 4

enter cells by fusion, exit by budding

Question 5

when do -RNA viruses become infectious?

Answer 5

once they have budded

Question 6

what 2 things are -RNA viruses sensitive to?

Answer 6

1. lipid solvents
2. drying

Question 7

what 2 diseases does rhabdovirus cause?

Answer 7

1. rabies
2. vesicular stomatitis

Question 8

what 2 diseases does paramyxovirus cause?

Answer 8

1. mumps
2. measles

Question 9

what is the shape of rhabdovirus?

Answer 9

bullet

Question 10

5 proteins in rhabdovirus

Answer 10

1. nucleocapsid protein
2. matrix protein
3. L and P proteins (RNA pol)
4. glycoprotein

Question 11

6 proteins in paramyxovirus

Answer 11

1. nucleoprotein
2. matrix protein
3. polymerase
4. phosphoprotein
5. fusion protein
6. hemagglutinin-neuraminidase

Question 12

when is rabies fatal?

Answer 12

once clinical symptoms are observed

Question 13

5 symptoms of rabies

Answer 13

1. excitement or agitation
2. hypersalivation
3. acute encephalomyelitis
4. coma
5. death

Question 14

progression of rabies infection (6 steps)

Answer 14

1. virus enters tissue from saliva from animal bite
2. virus replicates in muscle near bite
3. virus moves up peripheral nervous system to CNS
4. virus ascends spinal cord
5. virus reaches brain to cause fatal encephalitis
6. virus enters salivary glands and other organs

Question 15

what is the only way that rabies can travel? why?

Answer 15

can only travel in saliva bc virus cannot survive in open air/dry conditions

Question 16

describe the first artificially produced virus vaccine

Answer 16

Louis Pasteur dried rabbit spinal cords after rabies infection to make attenuated virus –> inoculation into animals protected them from disease

Question 17

are human rabies cases common in Asia, Africa, North America?

Answer 17

common in Asia and Africa but very rare in North America

Question 18

describe what happens to people exposed to bats

Answer 18

prophylactically vaccinated against rabies when exposed to bats

Question 19

what is mumps?

Answer 19

salivary gland and testicular infection

Question 20

what does RSV stand for?

Answer 20

Respiratory Syncytial Virus

Question 21

what does RSV cause?

Answer 21

bronchiolitis and pneumonia in infants and children

Question 22

what is the 2nd most common cause of respiratory tract disease in infants and children?

Answer 22

Human Parainfluenza Viruses (HPIV)

Question 23

What are 5 diseases that paramyxoviruses cause in other animals?

Answer 23

1. Canine distemper virus
2. Phocine distemper virus (seals)
3. Cetacean morbillivirus (dolphins)
4. Newcastle disease virus (birds)
5. Rinderpest virus (cattle)

Question 24

what are henipaviruses?

Answer 24

type of paramyxovirus that is a zoonotic pathogen –> occurs naturally in animals but also infects humans

Question 25

what does measles cause?

Answer 25

disseminated rash

Question 26

what is the most common cause of sterility?

Answer 26

mumps

Question 27

describe the processing of -RNA genomes

Answer 27

1. transcribed to make mRNA 2. translation of mRNA makes proteins for replication from +RNA to -RNA 3. new -RNA undergoes secondary transcription to make more viral proteins

Question 28

what were the 2 proposed models of transcription?

Answer 28

1. MULTIPLE PROMOTER 2. SINGLE ENTRY

Question 29

describe the multiple promoter model

Answer 29

there are multiple transcription promoters along the genome, each at the 3' end of each cistron --> RNA pol transcribes, falls off, jumps to the next one

Question 30

describe the single entry model

Answer 30

RNA pol binds 1 promoter and transcribes each cistron in sequence

Question 31

which transcription model is correct? how do we know?

Answer 31

the SINGLE ENTRY model is correct using UV radiation that makes dimers and stops transcription --> found that all protein production was blocked --> must be single entry

Question 32

describe the assay looking at molar abundance of RNA complementary to probe DNA

Answer 32

made oligonucleotide probes complementary to the 3' and 5' ends of the first 3 genes allow for hybridization --> both ends were synthesized at the same rates but 3' end made in greater molar abundance than 5' end

Question 33

what did they find from the assay looking at molar abundance of RNA complementary to probe DNA? 2 main things

Answer 33

found the time when transcription began --> let you find the RATE of transcription at intergenic region: 1. Pausing - polyadenylation at poly(U) tract by repetitive retranscription 2. Attenuation - polymerase falls of template during "stuttering" process

Question 34

why is VSV a good vaccine vector? (6)

Answer 34

1. it is a weak pathogen that cannot undergo recombination/reassortment/transformation 2. no integration 3. can elicit strong humoral and cellular immune responses 4. naturally infects at mucosal surfaces 5. recombinant VSVs can be made with large gene insertions into their genome 6. grows to high titers in vitro, allowing rapid purification of large amounts of virus/viral proteins

Question 35

what is the strategy for vaccination with VSV?

Answer 35

ring vaccination

Question 36

was VSV vaccine successful?

Answer 36

extent of efficacy was uncertain bc trial design and adverse effects occurred

Question 37

side effects of VSV vaccine

Answer 37

1. headache 2. fatigue 3. muscle pain