Family Alfin-like

The Alfin1-like family is first described by its founding member, Alfin1. The cDNA of Alfin1 was obtained by differential screening of a poly(A)+ library from salt-tolerant alfalfa cells, which encodes a protein with a Cys4 and His/Cys3 putative zinc-binding domain. The putative consensus binding site for Alfin1 is shown to contain two to five G-rich triplets with the conserved core of GNGGTG or GTGGNG (PMID:9869418). Alfin1-binding sites occur in promoters of genes expressed in roots of a wide variety of plant species. Overexpression of Alfin1 in transgenic alfalfa plants driven by the CaMV 35S promoter confers a many-fold increase in root growth under normal and saline conditions and does not adversely affect shoot growth (PMID:10750899). More recent research has purported that the zinc finger motif in Alfin1 is actually a canonical plant homeodomain (PHD) finger, which has not been implicated in DNA binding in other proteins thus far. Further studies are needed to determine whether Alfin1 binds to DNA through the PHD finger or via another unidentified motif. Alfin1-like proteins in Arabidopsis thaliana have been shown to localize to the nucleus and bind to H3K4me3/2 via plant homeodomain (PHD) fingers (PMID:19154204).