A novel class of plant proteins containing a homeodomain with a closely linked leucine zipper motif. |
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Authors: | I Ruberti G Sessa S Lucchetti G Morelli |
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Institution: | Dipartimento di Genetica e Biologia Molecolare, Università di Roma La Sapienza, Italy. |
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Abstract: | The homeobox, a 183 bp DNA sequence element, was originally identified as a region of sequence similarity between many Drosophila homeotic genes. The homeobox codes for a DNA-binding motif known as the homeodomain. Homeobox genes have been found in many animal species, including sea urchins, nematodes, frogs, mice and humans. To isolate homeobox-containing sequences from the plant Arabidopsis thaliana, a cDNA library was screened with a highly degenerate oligonucleotide corresponding to a conserved eight amino acid sequence from the helix-3 region of the homeodomain. Using this strategy two cDNA clones sharing homeobox-related sequences were identified. Interestingly, both of the cDNAs also contain a second element that potentially codes for a leucine zipper motif which is located immediately 3'' to the homeobox. The close proximity of these two domains suggests that the homeodomain-leucine zipper motif could, via dimerization of the leucine zippers, recognize dyad-symmetrical DNA sequences. |
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