Abstract
The approximately 200-nucleotide-long 3'-terminal noncoding region of tobacco mosaic virus (TMV) RNA contains a tRNA-like structure and, in its immediate upstream region, three consecutive pseudoknots, each of which is composed of two double-helical segments. To elucidate the biological functions of the pseudoknot region, we constructed several deletion mutant TMV-L (a tomato strain) RNAs by using an in vitro transcription system and tested their ability to multiply in both tobacco plants and protoplasts. When deletions were introduced just downstream of the termination codon of the coat protein gene in the 5'-to-3' direction progressively, five of six double-helical segments were dispensable for viral multiplication, indicating that the pseudoknot structures are not essential for multiplication. However, extension of the deletion into the central pseudoknot region resulted in reduction in viral multiplication, accompanied by loss of development of mosaic symptoms on systemic tobacco plants. Cessation of multiplication was observed when the sequence involved in formation of double-helical segment I just upstream of the tRNA-like structure was deleted irrespective of the start point and extent of deletion. Point mutations that destabilized double-helical segment I resulted in a loss or great reduction of viral multiplication, whereas the double mutants in which the double helix was restored by additional compensating base substitutions restored multiplication to nearly the wild-type level. Thus, double-helical segment I just upstream of the tRNA-like structure is a structural feature essential for viral multiplication.
Abstract from the paper’s OpenAlex record, shown for indexing and research. Copyright remains with the authors or the publisher. Read at the source ↗
The text the model read, with the source record’s inline markup (italics, sub- and superscripts) rendered and its character entities decoded; quote offsets refer to the raw text.
Claims 6
Claim · model-written summary
Five of six double-helical segments were dispensable for viral multiplication.
- Taxon
- tobacco plants
Nicotiana tabacume1 - Treatment
- five of six double-helical segmentse0
- Interactor
- tobacco mosaic virus
Tobacco mosaic viruse2pathogen - Outcome
- viral multiplicatione0
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“five of six double-helical segments were dispensable for viral multiplication”
e1“tobacco plants and protoplasts”
e2“tobacco mosaic virus (TMV)”
Claim · model-written summary
Deletion into the central pseudoknot reduced viral multiplication.
- Taxon
- tobacco plantsNicotiana tabacume1
- Treatment
- extension of the deletion into the central pseudoknot regione0
- Interactor
- tobacco mosaic virusTobacco mosaic viruse2pathogen
- Outcome
- viral multiplicatione0
- Direction
- reductione0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“extension of the deletion into the central pseudoknot region resulted in reduction in viral multiplication”
e1“tobacco plants and protoplasts”
e2“tobacco mosaic virus (TMV)”
Claim · model-written summary
Deletion into the central pseudoknot caused loss of mosaic symptoms in systemic tobacco plants.
- Taxon
- tobacco plantsNicotiana tabacume0
- Treatment
- extension of the deletion into the central pseudoknot regione0
- Interactor
- tobacco mosaic virusTobacco mosaic viruse1pathogen
- Outcome
- development of mosaic symptomse0
- Direction
- losse0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“extension of the deletion into the central pseudoknot region resulted in reduction in viral multiplication, accompanied by loss of development of mosaic symptoms on systemic tobacco plants”
e1“tobacco mosaic virus (TMV)”
Claim · model-written summary
Deletion of the sequence forming segment I stopped viral multiplication regardless of deletion extent.
- Taxon
- tobacco plantsNicotiana tabacume1
- Treatment
- sequence involved in formation of double-helical segment I just upstream of the tRNA-like structure was deletede0
- Interactor
- tobacco mosaic virusTobacco mosaic viruse2pathogen
- Outcome
- multiplicatione0
- Direction
- Cessatione0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Cessation of multiplication was observed when the sequence involved in formation of double-helical segment I just upstream of the tRNA-like structure was deleted irrespective of the start point and extent of deletion”
e1“tobacco plants and protoplasts”
e2“tobacco mosaic virus (TMV)”
Claim · model-written summary
Mutations destabilizing segment I eliminated or greatly reduced viral multiplication.
- Taxon
- tobacco plantsNicotiana tabacume1
- Treatment
- Point mutations that destabilized double-helical segment Ie0
- Interactor
- tobacco mosaic virusTobacco mosaic viruse2pathogen
- Outcome
- viral multiplicatione0
- Direction
- loss or great reductione0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Point mutations that destabilized double-helical segment I resulted in a loss or great reduction of viral multiplication”
e1“tobacco plants and protoplasts”
e2“tobacco mosaic virus (TMV)”
Claim · model-written summary
Compensating substitutions restoring the helix restored multiplication near wild-type level.
- Taxon
- tobacco plantsNicotiana tabacume1
- Treatment
- additional compensating base substitutionse0
- Interactor
- tobacco mosaic virusTobacco mosaic viruse2pathogen
- Outcome
- multiplicatione0
- Direction
- restorede0
- Comparator
- wild-type levele0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“double mutants in which the double helix was restored by additional compensating base substitutions restored multiplication to nearly the wild-type level”
e1“tobacco plants and protoplasts”
e2“tobacco mosaic virus (TMV)”
The same questions in other papers
loss of function · Tobacco mosaic virus · Nicotiana tabacum (tobacco)Positive and negative results
5 papers in the same direction as this paper · 12 in the opposite direction
- negative
- negative
- negative
14 papers more in this group
See all 18 papers →Claims are grouped by organism, treatment and what was measured or targeted. A paper counts as positive when any of its claims in the group is positive.