This entry represents a domain found in viral DNA replication helicases, bacterial ATP-dependent DNA helicase Pif1 and eukaryotic ATP-dependent DNA helicase PIF7.
This entry includes a group of DNA helicases, including Pif1 and Rrm3 from budding yeasts and Pfh1 from fusion yeast. This entry also includes Pif1 like proteins from prokaryotes and eukaryotes including plants. Pif1 is a DNA helicase conserved from bacteria to humans [, ]. It suppresses both G-quadruplex-associated DNA damage and telomere lengthening. In budding yeast, it exists in two forms, nuclear form and mitochondrial form. Its nuclear form inhibits telomerase, while its mitochondrial form is involved in repair and recombination of mitochondrial DNA [, ]. In budding yeasts, another DNA replicative helicase, Rrm3 is recruited to paused replisomes to promote fork progression throughout nonhistone protein-DNA complexes, naturally occurring impediments that are encountered in each S phase where replication forks pauses []. It shares protein sequence similarities with another DNA helicase, Pif1. However, their functions are different. Rrm3promotes telomere replication, while Pif1 inhibits telomere replication []. They also have opposite effects on replication fork progression in ribosomal DNA [].In fission yeasts, Pfh1 is required for the maintenance of both mitochondrial and nuclear genome stability [, ].
This entry represents ATP-dependent DNA helicase Rrm3 from buddingyeasts. It is a 5' to 3' DNA replicative helicase recruited to paused replisomes to promote fork progression throughout nonhistone protein-DNA complexes, naturally occurring impediments that are encountered in each S phase where replication forks pauses []. It shares protein sequence similarities with another DNA helicase, Pif1. However, their functions are different. Rrm3 promotes telomere replication, while Pif1 inhibits telomere replication []. They also have opposite effects on replication fork progression in ribosomal DNA [].
This entry represents a group of plant helix-loop-helix (bHLH) transcription factors, including ALC, PIFs (phy-interacting factors) and SPATULA from Arabidopsis [, ]. ALC enables cell separation in fruit dehiscence, the processes in which the fruit opens and releases the seed []. PIF1 regulates chlorophyll biosynthesis to optimise the greening process []. PIF5 is involved in ethylene biosynthesis and phytochrome signalling []. SPATULA plays a role in floral organogenesis [].
This family represents a group of plant thioredoxin-like fold domain-containing proteins, including MRL7 (Protein MESOPHYLL-CELL RNAI LIBRARY LINE 7, also known as Protein EARLY CHLOROPLAST BIOGENESIS 1 (ECB1) or Protein SUPPRESSOR OF VARIEGATION 4 SVR4) and its paralog MRL7L from Arabidopsis. These proteins are required for early chloroplast development and involved in the regulation of plastid gene expression [, , , , ]. They also mediate the degradation of two repressors of chloroplast biogenesis, PIF1 and PIF3 in nucleus []. MRL7L is a necessary component of phytochrome signalling for photosynthesis-associated plastid-encoded genes (PhAPGs) activation [].
