Al. Rubinstein et al., PEX1, A POLLEN-SPECIFIC GENE WITH AN EXTENSIN-LIKE DOMAIN, Proceedings of the National Academy of Sciences of the United Statesof America, 92(8), 1995, pp. 3086-3090
We report here the identification of a pollen-specific gene from Zea m
ays that contains multiple Ser-(Pro)(n) repeats, the motif found in th
e cell wall-associated extensins. Sequence analysis reveals that the e
ncoded protein has a putative globular domain at the N terminus and an
extensin-like domain at the C terminus. The Pex1 (pollen extensin-lik
e) gene is expressed exclusively in pollen, not in vegetative or femal
e tissues, and is not induced in leaves upon wounding. We propose that
the encoded protein may have a role in reproduction, either as a stru
ctural element deposited in the pollen tube wall during its rapid grow
th or as a sexual recognition molecule that interacts with partner mol
ecules in the pistil.