Jp. Renaudin et al., CLONING OF 4 CYCLINS FROM MAIZE INDICATES THAT HIGHER-PLANTS HAVE 3 STRUCTURALLY DISTINCT GROUPS OF MITOTIC CYCLINS, Proceedings of the National Academy of Sciences of the United Statesof America, 91(15), 1994, pp. 7375-7379
While a large number of cyclins have been described in animals and yea
sts, very limited information is available regarding cyclins in plants
. We describe here the isolation of cDNA clones encoding four putative
mitotic cyclins from maize. All four cyclins were able to induce matu
ration of Xenopus oocytes, demonstrating that they can act as mitotic
cyclins in this system. Northern analysis showed that all four cyclins
were expressed only in actively dividing tissues and organs, with a s
tronger correlation between expression and mitotic activity than is ob
served with cdc2. The deduced protein sequences suggest that the four
maize cyclins belong to the cyclin A and B families identified from an
imal and yeast studies but that they cannot be described easily as eit
her A-type or B-type cyclins. However, comparison with previously clon
ed plant cyclins shows that cyclins in higher plants form three distin
ct structural groups that have been conserved in both monocotyledonous
and dicotyledonous species and that cyclins from all three groups are
present within a single plant species.