InterPro: IPR001313 Pumilio RNA-binding repeat

The drosophila pumilio gene codes for an unusual protein that binds through the Puf domain that usually occurs as a tandem repeat of eight domains. The FBF-2 protein of Caenorhabditis elegans also has a Puf domain. Both proteins function as translational repressors in early embryonic development by binding sequences in the 3' UTR of target mRNAs [1, 2]. The same type of repetitive domain has been found in in a number of other proteins from all eukaryotic kingdoms. The Puf proteins characterised to date have been reported to bind to 3'-untranslated region (UTR) sequences encompassing a so-called UGUR tetranucleotide motif and thereby to repress gene expression by affecting mRNA translation or stability.

In Saccharomyces cerevisiae (Baker's yeast), five proteins, termed Puf1p to Puf5p, bear six to eight Puf repeats [3]. Puf3p binds nearly exclusively to cytoplasmic mRNAs that encode mitochondrial proteins; Puf1p and Puf2p interact preferentially with mRNAs encoding membrane-associated proteins; Puf4p preferentially binds mRNAs encoding nucleolar ribosomal RNA-processing factors; and Puf5p is associated with mRNAs encoding chromatin modifiers and components of the spindle pole body. This suggests the existence of an extensive network of RNA-protein interactions that coordinate the post-transcriptional fate of large sets of cytotopically and functionally related RNAs through each stage of its lifecycle.