InterPro domain: IPR040222

This entry represents a group of ALOG (Arabidopsis LSH1 and Oryza G1) domain containing proteins, including LSH1-10 from Arabidopsis and G1/G1L1-8 from rice. G1 may be involved in transcriptional regulation and specifies sterile lemma identity in the rice spikelet [ 1 ]. LSH1 is involved in phytochrome-mediated light signaling and in shoot meristem identity [ 2 ]. The expression of LSH3 and LSH4 can be regulated by CUC1, which may suppress organ differentiation in the boundary region [ 3 ].

The 125-residue ALOG (Arabidopsis LSH1 and oryza G1) domain is rich in basicamino acids, especially arginine, and is highly conserved among land plants.Members of the ALOG family of proteins function as key developmentalregulators. It has been proposed that the ALOG domain originated from the N-terminal DNA-binding domains of integrases belonging to the tyrosinerecombinase superfamily encoded by a distinct type of DIRS1-like LTRretrotransposon found in several eukaryotes. Secondary structure predictionsrevealed an all-alpha helical domain with four conserved helices [ 4 , 4 ].

1. The homeotic gene long sterile lemma (G1) specifies sterile lemma identity in the rice spikelet. Proc. Natl. Acad. Sci. U.S.A. 106, 20103-8
2. Overexpression of LSH1, a member of an uncharacterised gene family, causes enhanced light regulation of seedling development. Plant J. 37, 694-706
3. CUP-SHAPED COTYLEDON1 transcription factor activates the expression of LSH4 and LSH3, two members of the ALOG gene family, in shoot organ boundary cells. Plant J. 66, 1066-77
4. ALOG domains: provenance of plant homeotic and developmental regulators from the DNA-binding domain of a novel class of DIRS1-type retroposons. Biol. Direct 7, 39