High impact information on VAR1

• The majority of VAR1 appears to exist as heterocomplexes with VAR2, whereas VAR2 may be present as homocomplexes as well [1].
• The immutans (im) mutant of Arabidopsis shows a variegated phenotype comprising albino and green somatic sectors [2].
• Mutations in the Arabidopsis gene IMMUTANS cause a variegated phenotype by inactivating a chloroplast terminal oxidase associated with phytoene desaturation [2].
• Sequence analysis of one of the new restriction fragments found in the variegated plants suggested that it was the product of a rearrangement event involving regions of the mitochondrial genome [3].
• Nuclear recessive mutations at the chloroplast mutator (CHM) locus of Arabidopsis produce a variegated phenotype that is inherited in a non-Mendelian fashion [3].

Biological context of VAR1

• The presence of these restriction fragments cosegregated with the variegated phenotype in the progeny of crosses between mutant and wild-type plants [3].
• Outcrosses of B- and C-insert homozygotes to wild-type plants resulted in F1 plants that were variegated [4].
• The Arabidopsis immutans mutation affects plastid differentiation and the morphogenesis of white and green sectors in variegated plants [5].

Anatomical context of VAR1

• This finding suggests that VAR1 and VAR2 play a predominant role in the photosystem II repair cycle in thylakoid membranes [1].
• Based on these results, we conclude that VAR1 and VAR2 are the major components of an FtsH complex involved in the repair of photodamaged proteins in thylakoid membranes [1].
• BACKGROUND: A leaf-variegated mutation var1 of Arabidopsis results in the development of abnormal plastids and the formation of a green/white sector [6].

Associations of VAR1 with chemical compounds

• Nineteen mutants displaying high levels of somatic Ac activity, as judged by their highly variegated phenotypes, were isolated after screening the M2 generation on streptomycin-containing medium [7].

Other interactions of VAR1

• These observations led us to examine whether VAR1 and VAR2 form a complex [1].
• The stable, recessive Arabidopsis variegated 3 (var3) mutant exhibits a variegated phenotype due to somatic areas lacking or containing developmentally retarded chloroplasts and greatly reduced numbers of palisade cells [8].
• Nongreen sectors of variegated leaves lacking Thf1 expression contain plastids that accumulate membrane vesicles on the interior and lack organized thylakoid structures [9].

References