GEO 数据集

主题由标题与摘要自动归类；样本量为数据集标注之和，SuperSeries 可能与其 SubSeries 重复计算。

• VIPP1/pTAC4 indirectly supports PEP accumulation and RpoB occupancy on chloroplast DNA
  GSE339035Arabidopsis thaliana108 个样本2026-10-27

  Chloroplast DNA together with proteins and RNAs form nucleoids, where genomes are stored, replicated and expressed. VIPP1/pTAC4 is a conserved membrane-associated protein previously identified in chloroplast nucleoid fractions, suggesting a possible role of this protein in linking plastid DNA, thylakoid membranes, and transcription. Here, we used plastid ChIP-seq to test whether VIPP1/pTAC4 directly affects plastid-encoded RNA polymerase (PEP) association with chloroplast DNA. Loss of VIPP1/pTAC4 caused a genome-wide reduction in RpoB occupancy, but we found no evidence of VIPP1/pTAC4 binding to chloroplast DNA. Likewise, the VIPP1-interacting protein VIA1 did not detectably bind chloroplast DNA, but was not required for normal RpoB occupancy. Comparison with other non-photosynthetic mutants and immunoblot analyses indicated that reduced PEP occupancy in ptac4 is likely an indirect consequence of impaired chloroplast development and reduced PEP core subunit accumulation. These findings challenge a direct role of VIPP1/pTAC4 in the chloroplast nucleoid and highlight the pleiotropic effects of chloroplast biogenesis defects on plastid transcription.