SVR4 (suppressor of variegation 4) and SVR4-like: two proteins with a role in proper organization of the chloroplast genetic machinery

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 - Nielsen, Agnieszka Janina Zygadlo

AU - Melonek, Jonna

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.

U2 - 10.1111/ppl.12108

DO - 10.1111/ppl.12108

M3 - Journal article

C2 - 24111559

SN - 0031-9317

VL - 150

SP - 477

EP - 492

JO - Physiologia Plantarum

JF - Physiologia Plantarum

IS - 3

ER -