dc.identifier.uri |
http://dx.doi.org/10.15488/12806 |
|
dc.identifier.uri |
https://www.repo.uni-hannover.de/handle/123456789/12909 |
|
dc.contributor.author |
Niehaus, Markus
|
eng |
dc.date.accessioned |
2022-10-10T09:39:49Z |
|
dc.date.available |
2022-10-10T09:39:49Z |
|
dc.date.issued |
2022 |
|
dc.identifier.citation |
Niehaus, Markus: The deoxypyrimidine nucleotide metabolism in plant mitochondria. Hannover : Gottfried Wilhelm Leibniz Universität, Diss., 2022, vi, Seite 7 - 178, DOI: https://doi.org/10.15488/12806 |
eng |
dc.description.abstract |
The synthesis of deoxythymidine triphosphate (dTTP), as one of the four building blocks of
DNA, plays a crucial role for the plant. Each cell compartment with its own sub genome
therefore has a subset of enzymes necessary for the formation of thymidylates. However, the
respective compartments are not purely self-sufficient systems, but are in constant exchange
and can support each other depending on the developmental stage. Furthermore, the
contribution of individual steps of thymidylate metabolism to the thymidylate pools varies in
importance over time.
According to current knowledge, the essential enzymes involved in the synthesis of dTTP in
Arabidopsis thaliana are Dihydrofolate Reductase-Thymidilate Synthase (DHFR-TS),
Thymidine Kinase (TK) and Deoxythymidine Monophosphate Kinase (TMPK, ZEU1). Complete
loss of these enzymes is lethal for the plant, or in the case of TK, leads to a plant that can no
longer reproduce. However, in the case of DHFR-TS and TK, only one of the two homologues
is required for the development of a viable plant.
This work shows that at germination, de novo biosynthesis, which proceeds via DHFR-TS, plays
a minor role compared to salvage. However, the exclusively mitochondrial DHFR-TS2
isoenzyme appears to be more important than its cytosolic counterpart DHFR-TS1. A similar
picture emerges for salvage. TK1b, present in chloroplasts and mitochondria, plays a more
important role than its cytosolic representative TK1a. Particularly the chloroplastic TK1b has a
greater impact in supplying the cell with thymidylates, which coincides with the synthesis of
cpDNA being also the greatest sink during this time. A TK1b mutant shows a severe arrest in
cpDNA synthesis during germination. The synthesis of cpDNA is partially restored in the
established seedling and thymidylate pools are then also affected in a mutant lacking cytosolic
TK1a suggesting that the supply of thymidylates is then secured by both cytosolic and
organellar salvage.
Among the less important enzymes, appear to be dUTP Pyrophosphatase 1 localized in
chloroplasts and mitochondria (DUT1org) and dCMP Deaminase (DCD) localized in
mitochondria. Both enzymes play a minor role in providing dUMP for DHFR-TS. In neither of
the two associated mutants a serious disruption of thymidylate formation is observable. This
may be due to an involvement of both enzymes in the formation of dUMP, as indicated by
preliminary data suggesting that a DCD DUT1org mutant is not viable. |
eng |
dc.language.iso |
eng |
eng |
dc.publisher |
Hannover : Institutionelles Repositorium der Leibniz Universität Hannover |
|
dc.rights |
Es gilt deutsches Urheberrecht. Das Dokument darf zum eigenen Gebrauch kostenfrei genutzt, aber nicht im Internet bereitgestellt oder an Außenstehende weitergegeben werden. |
eng |
dc.subject |
deoxyribonucleosides |
eng |
dc.subject |
thymidylates |
eng |
dc.subject |
germination |
eng |
dc.subject |
Arabidopsis thaliana |
eng |
dc.subject |
Deoxyribonukleotide |
ger |
dc.subject |
Thymidilate |
ger |
dc.subject |
Keimung |
ger |
dc.subject |
Arabidopsis thaliana |
ger |
dc.subject.ddc |
500 | Naturwissenschaften
|
eng |
dc.title |
The deoxypyrimidine nucleotide metabolism in plant mitochondria |
eng |
dc.type |
DoctoralThesis |
eng |
dc.type |
Text |
eng |
dc.relation.doi |
10.1104/pp.19.00736 |
|
dc.relation.doi |
10.1093/plcell/koaa028 |
|
dc.relation.doi |
10.1007/978-1-0716-2176-9_9 |
|
dc.relation.doi |
10.1093/plcell/koac207 |
|
dc.description.version |
publishedVersion |
eng |
tib.accessRights |
frei zug�nglich |
eng |