High impact information on VRN1

• This association did not depend on vernalization or VRN2 function and was maintained during mitosis but was lost in meiotic chromosomes, suggesting that VRN1 may contribute to chromatin silencing that is not meiotically stable [1].
• Like LHP1, VRN1 functions in both flowering-time control and vernalization [1].
• Using 6,190 gametes, we found VRN1 to be completely linked to MADS-box genes AP1 and AGLG1 in a 0.03-centimorgan interval flanked by genes Cysteine and Cytochrome B5 [2].
• No differences were detected between genotypes with different VRN1 alleles in the AP1 and AGLG1 coding regions, but three independent deletions were found in the promoter region of AP1 [2].
• The stable silencing of FLC also requires the DNA-binding protein VERNALIZATION1 (VRN1) and the polycomb-group protein VRN2 [3].

Biological context of VRN1

• We explored the localization of VRN1 and found it to be associated generally with Arabidopsis chromosomes but not the heterochromatic chromocenters [1].
• VRN1 mRNA is not induced by phosphate starvation, indicating that its accumulation during senescence is not due to a self-induced defect in utilizing phosphates [4].
• These observations imply that VRN1 may promote RNA degradation during senescence of somatic cells in V. carteri, and that its regulation has similarity with that of certain senescence-associated RNases in higher plants [4].
• Regulation of VRN-1 vernalization genes in normal and transgenic polyploid wheat [5].
• Here, we confirm this prediction in young isogenic lines of hexaploid wheat carrying different dominant Vrn-A1, Vrn-B1, and Vrn-D1 alleles, and also in heterozygous VRN-1 diploid wheat plants [5].

Associations of VRN1 with chemical compounds

• The vernalization gene VRN-1 plays an important role in this process in diploid (Triticum monococcum) and polyploid wheat (Triticum aestivum) [5].

Regulatory relationships of VRN1

• These results suggest that the dominant Vrn-1 allele or a gene regulated by VRN-1 down-regulates the VRN-2 repressor facilitating the transcription of the recessive alleles in unvernalized plants [5].

Other interactions of VRN1

• VRN1 encodes a protein that binds DNA in vitro in a non-sequence-specific manner and functions in stable repression of the major target of the vernalization pathway, the floral repressor FLC [6].
• These results suggest that AP1 is a better candidate for VRN1 than AGLG1 [2].
• The corresponding cDNA clone VRN1, encoding an S-like RNase of V. carteri, is the first T(2)/S-like RNase to be cloned from green algae [4].
• Semi-quantitative RT-PCR analysis revealed that a relative amount of VRN1 mRNA is more than three-fold higher in the senescent somatic cells than in young somatic cells when the mRNA of ribosomal protein S18 is used as an internal standard [4].
• The vrn1 and vrn2 mutations did not affect the acclimation response as judged by expression of cold-induced transcripts and freezing tolerance assays. vrn1-1 affected the short-day vernalization response of Landsberg erecta and reduced the vernalization response of other late-flowering Arabidopsis mutants [7].

Analytical, diagnostic and therapeutic context of VRN1

• Allelism tests showed that these mutations fall into at least three complementation groups defining three loci named VRN 1, 2 and 3 [7].

References