Alpha-tubulin gene family of maize (Zea mays L.). Evidence for two ancient alpha-tubulin genes in plants.
Among 81 alpha-tubulin cDNA clones prepared from RNA from maize seedling shoot, endosperm and pollen, we identified six different alpha-tubulin coding sequences. The DNA sequence analysis of coding and non-coding regions from the clones showed that they can be classified into three different alpha-tubulin gene subfamilies. Genes within each subfamily encode proteins that are 99 to 100% identical in amino acid sequence. Deduced amino acid sequence identity between genes in different subfamilies ranges from 89 to 93%. The results of hybridizations of genomic DNAs to alpha-tubulin coding region probes and to 3' non-coding region probes constructed from six different alpha-tubulin cDNA clones indicated that the maize alpha-tubulin gene family contains at least eight members. Comparison of deduced alpha-tubulin amino acid sequences from maize and the dicot species Arabidopsis thaliana showed that alpha-tubulin isotypes encoded by genes in maize subfamilies I and II are more similar to specific Arabidopsis gene products (96 to 97% amino acid identity) than to isotypes encoded by genes in the other maize subfamilies. Phylogenetic analyses revealed that genes in these two subfamilies were derived from two ancient alpha-tubulin genes that predate the divergence of monocots and dicots. These same analyses revealed that the gene in maize subfamily III is more closely related to sequences from subfamily I genes than to those from subfamily II genes. However, the subfamily III gene has no close counterpart in Arabidopsis. We found evidence of a transposable element-like insertion in the subfamily III gene in some maize lines.
Villemur
R
R
Department of Genetics and Cell Biology, University of Minnesota, St Paul 55108.
Joyce
C M
CM
Haas
N A
NA
Goddard
R H
RH
Kopczak
S D
SD
Hussey
P J
PJ
Snustad
D P
DP
Silflow
C D
CD
D001483:Base Sequence; D005075:Biological Evolution; D003001:Cloning, Molecular; D003062:Codon; D004247:DNA / Q000235:genetics; D017343:Genes, Plant; D008969:Molecular Sequence Data; D005810:Multigene Family; D016415:Sequence Alignment; D013045:Species Specificity; D014404:Tubulin / Q000235:genetics*; D003313:Zea mays / Q000235:genetics*
D003062:Codon; D014404:Tubulin; D004247:DNA