Table 2.

Conservation of CUL4-DDB1^CDT2 and SCF^Skp2 components in prokaryotic and eukaryotic species.

Group	Phylum or Division	Species	Cullins*	DDB1	CDT2	Skp1	Skp2
Eubacteria	Aquificae	Aquifex aeolicus	-	-	-	-	-
	Firmicutes	Bacillus subtilis	-	-	-	-	-
	Proteobacteria	Escherichia coli	-	-	-	-	-
Archaea	Crenarchaeota	Aeropyrum pernix	-	-	-	-	-
	Euryarchaeota	Methanocaldococcus jannaschii	-	-	-	-	-
Protist	Apicomplexa	Plasmodium falciparum	2 (1, 4)		-		-
	Euglenozoa	Leishmania infantum	7 (1, 1, 3, 3, 3, 4, 4)		-		-
Slime Mold	Amoebozoa	Dictyostelium discoideum	5 (1, 1, 1, 3, 4)		-		-
Plant	Magnoliophyta	Arabidopsis thaliana	9 (1, 3, 3, 3, 4, 4, 4, 4, 4)				-
	Magnoliophyta	Oryza sativa	9 (1, 3, 3, 3, 3, 4, 4, 4, 4)				-
Fungi	Ascomycota	Saccharomyces cerevisiae	3 (1, 2, 3)	-	-		-
	Ascomycota	Schizosaccharomyces pombe	3 (1, 3, 4)				-
	Basidiomycota	Cryptococcus neoformans	7 (1, 1, 1, 1, 3, 3, 4)				-
Invertebrate	Nematoda	Caenorhabditis elegans	6 (1, 1, 2, 3, 4, 5)
	Arthropoda	Drosophila melanogaster	5 (1, 1, 2, 3, 4)
Vertebrate	Chordata	Danio rerio	8 (1, 1, 1, 2, 3, 3, 4, 4)**
	Chordata	Xenopus laevis	6 (1, 1, 2, 3, 3, 4)
Mammalian	Chordata	Mus musculus	6 (1, 2, 3, 4, 4, 5)
	Chordata	Bos taurus	6 (1, 2, 3, 4, 4, 5)
	Chordata	Homo sapiens	7 (1, 2, 3, 4, 4, 5, 7)

A recognizable homolog in the species is designated by a check mark, and the absence of a homolog by a dash.

* The number of cullins is recorded in each organism. The metazoan cullin (CUL1-CUL5) for which each cullin is most related (by reciprocal BLAST analysis) is indicated in parentheses (e.g., 2 (1, 4) = two cullins that are most related to CUL1 and CUL4, respectively). The divergent CUL7 is listed separately for humans.

**For Danio rerio (zebrafish), genes that were predicted to encode cullin proteins of less than 100 amino acids were not included.