Abstract
We investigated the function of cell wall hydroxyproline-rich glycoproteins by observing the effects of a selective inhibitor of prolyl hydroxylase, 3,4-dehydro-L-proline (Dhp), on wall regeneration by Nicotiana tabacum mesophyll cell protoplasts. Protoplasts treated with micromolar concentrations of Dhp do not develop osmotic stability and do not initiate mitosis. The architecture of regenerated cell walls was examined using deep-etch, freeze-fracture electron microscopy of rapidly frozen tobacco cells. Untreated protoplasts assemble a dense fibrillar cell wall consisting of laterally associating subelementary fibrils. In contrast, treatment of protoplasts with Dhp alters the structure of the regenerated wall fibrils in several ways: first, the microfibrils are coated with globular knobs; second, some larger fiber bundles have an open ribbon-like appearance; and third, the smallest subelementary fibrils were not visible. Tobacco cells develop an abnormal morphology as a consequence of this abnormal cell wall structure. Thus, inhibition of prolyl hydroxylase results in the regeneration of a cell wall with abnormal structural and functional properties. These data provide experimental evidence that hydroxyproline-rich glycoproteins are important for the structural integrity of primary cell walls and for the correct assembly of other wall polymers, and that wall structure is an important regulator of cell division and cell morphology.
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Claims 9
Claim · model-written summary
Dhp-treated tobacco protoplasts did not develop osmotic stability.
- Taxon
- Nicotiana tabacum
Nicotiana tabacumt0 - Treatment
- Dhpe0
- Outcome
- osmotic stabilitye0
- Direction
- do not develope0
- Qualifier
- micromolar concentrationse0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Protoplasts treated with micromolar concentrations of Dhp do not develop osmotic stability”
t0“Nicotiana tabacum”
Claim · model-written summary
Dhp-treated tobacco protoplasts did not initiate mitosis.
- Taxon
- Nicotiana tabacumNicotiana tabacumt0
- Treatment
- Dhpe0
- Outcome
- mitosise0
- Direction
- do not initiatee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Protoplasts treated with micromolar concentrations of Dhp do not develop osmotic stability and do not initiate mitosis”
t0“Nicotiana tabacum”
Claim · model-written summary
Untreated protoplasts assembled a dense fibrillar cell wall of laterally associating subelementary fibrils.
- Taxon
- Nicotiana tabacumNicotiana tabacumt0
- Treatment
- Untreatede0
- Outcome
- dense fibrillar cell wall consisting of laterally associating subelementary fibrilse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Untreated protoplasts assemble a dense fibrillar cell wall consisting of laterally associating subelementary fibrils”
t0“Nicotiana tabacum”
Claim · model-written summary
Dhp-treated protoplasts formed microfibrils coated with globular knobs.
- Taxon
- Nicotiana tabacumNicotiana tabacumt0
- Treatment
- Dhpe0
- Outcome
- microfibrils are coated with globular knobse0
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“treatment of protoplasts with Dhp alters the structure of the regenerated wall fibrils in several ways: first, the microfibrils are coated with globular knobs”
t0“Nicotiana tabacum”
Claim · model-written summary
Dhp-treated protoplasts formed larger fiber bundles with an open ribbon-like appearance.
- Taxon
- Nicotiana tabacumNicotiana tabacumt0
- Treatment
- Dhpe1
- Outcome
- larger fiber bundles have an open ribbon-like appearancee0
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“some larger fiber bundles have an open ribbon-like appearance”
e1“treatment of protoplasts with Dhp alters the structure of the regenerated wall fibrils”
t0“Nicotiana tabacum”
Claim · model-written summary
The smallest subelementary fibrils were not visible after Dhp treatment.
- Taxon
- Nicotiana tabacumNicotiana tabacumt0
- Treatment
- Dhpe1
- Outcome
- smallest subelementary fibrils were not visiblee0
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the smallest subelementary fibrils were not visible”
e1“treatment of protoplasts with Dhp alters the structure of the regenerated wall fibrils”
t0“Nicotiana tabacum”
Claim · model-written summary
Tobacco cells developed abnormal morphology as a consequence of abnormal wall structure.
- Taxon
- TobaccoNicotiana tabacume0
- Outcome
- abnormal morphologye0
- Qualifier
- abnormal cell wall structuree0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Tobacco cells develop an abnormal morphology as a consequence of this abnormal cell wall structure”
Claim · model-written summary
The authors infer that hydroxyproline-rich glycoproteins support primary wall integrity and correct assembly of other wall polymers.
- Taxon
- Nicotiana tabacumNicotiana tabacumt0
- Outcome
- structural integrity of primary cell walls and for the correct assembly of other wall polymerse0
- Qualifier
- hydroxyproline-rich glycoproteinse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“hydroxyproline-rich glycoproteins are important for the structural integrity of primary cell walls and for the correct assembly of other wall polymers”
t0“Nicotiana tabacum”
Claim · model-written summary
The authors infer that wall structure regulates cell division and morphology.
- Taxon
- Nicotiana tabacumNicotiana tabacumt0
- Outcome
- cell division and cell morphologye0
- Qualifier
- wall structuree0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“wall structure is an important regulator of cell division and cell morphology”
t0“Nicotiana tabacum”