TY - JOUR
T1 - SVR4 (suppressor of variegation 4) and SVR4-like
T2 - Two proteins with a role in proper organization of the chloroplast genetic machinery
AU - Powikrowska, Marta
AU - Khrouchtchova, Anastassia
AU - Martens, Helle Juel
AU - Zygadlo-Nielsen, Agnieszka
AU - Melonek, Joanna
AU - Schulz, Alexander
AU - Krupinska, Karin
AU - Rodermel, Steven
AU - Jensen, Poul Erik
PY - 2014/3
Y1 - 2014/3
N2 - SUPPRESSOR OF VARIEGATION 4 (SVR4, also called MRL7) and its homolog SVR4-like (also called MRL7-Like) were originally identified as important proteins for proper function of the chloroplast in Arabidopsis. Both are nuclear-encoded chloroplast-located proteins, and knockout mutants of either gene result in seedling lethality. Transmission electron microscopy analysis revealed that chloroplast development is arrested at an early developmental stage in both mutants. Accordingly, in the mutant plants severely decreased levels of photosynthetic pigments as well as subunits of the photosynthetic complexes could be detected. In absence of either of the two proteins chloroplast DNA organization was clearly affected. Immunological analysis revealed that SVR4 is a component of the transcriptionally active chromosome (TAC) from barley chloroplasts. Analyses of gene expression indicate that SVR4 and SVR4-like are required for proper function of the plastid transcriptional machinery. We propose that SVR4 and SVR4-like function as molecular chaperones ensuring proper organization of the nucleoids in chloroplasts.
AB - SUPPRESSOR OF VARIEGATION 4 (SVR4, also called MRL7) and its homolog SVR4-like (also called MRL7-Like) were originally identified as important proteins for proper function of the chloroplast in Arabidopsis. Both are nuclear-encoded chloroplast-located proteins, and knockout mutants of either gene result in seedling lethality. Transmission electron microscopy analysis revealed that chloroplast development is arrested at an early developmental stage in both mutants. Accordingly, in the mutant plants severely decreased levels of photosynthetic pigments as well as subunits of the photosynthetic complexes could be detected. In absence of either of the two proteins chloroplast DNA organization was clearly affected. Immunological analysis revealed that SVR4 is a component of the transcriptionally active chromosome (TAC) from barley chloroplasts. Analyses of gene expression indicate that SVR4 and SVR4-like are required for proper function of the plastid transcriptional machinery. We propose that SVR4 and SVR4-like function as molecular chaperones ensuring proper organization of the nucleoids in chloroplasts.
UR - http://www.scopus.com/inward/record.url?scp=84893794926&partnerID=8YFLogxK
U2 - 10.1111/ppl.12108
DO - 10.1111/ppl.12108
M3 - Article
SN - 0031-9317
VL - 150
SP - 477
EP - 492
JO - Physiologia Plantarum
JF - Physiologia Plantarum
IS - 3
ER -