Abstract
The products of the S-locus expressed in female tissues of Nicotiana alata are ribonucleases (S-RNases). The arrest of growth of incompatible pollen tubes in styles may result from entry of the S-RNase into the pollen tube and degradation of pollen tube RNA. We investigated the action of isolated S-RNases on pollen tubes grown in vitro and found that S-RNase is taken up by the pollen without substantial alteration. The S-RNases inhibit incorporation of exogenously added radioactive amino acids into protein by the germinated pollen. The S-RNases also inhibit in vitro translation of pollen tube RNA in a wheat germ cell-free extract. We found no evidence for a specific mRNA substrate for the S-RNases, which implies that if RNase activity is involved in the control of self-incompatibility, allelic specificity is more likely to depend on the selective uptake of S-RNases into pollen tubes or their selective activation or inactivation by pollen factors, rather than cleavage of a specific substrate. Heat treating S2-RNase largely destroys its RNase activity but increases its inhibitory effect on in vitro pollen tube growth. This effect is not due to an increased uptake of S2-RNase by the pollen but is associated with a greatly enhanced accumulation of S2-RNase on the outer surface of the pollen grains.
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- Anderson M. A., McFadden G. I., Bernatzky R., Atkinson A., Orpin T., Dedman H., Tregear G., Fernley R., Clarke A. E. Sequence variability of three alleles of the self-incompatibility gene of Nicotiana alata. Plant Cell. 1989 May;1(5):483–491. doi: 10.1105/tpc.1.5.483. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Bradford M. M. A rapid and sensitive method for the quantitation of microgram quantities of protein utilizing the principle of protein-dye binding. Anal Biochem. 1976 May 7;72:248–254. doi: 10.1006/abio.1976.9999. [DOI] [PubMed] [Google Scholar]
- Clark K. R., Okuley J. J., Collins P. D., Sims T. L. Sequence variability and developmental expression of S-alleles in self-incompatible and pseudo-self-compatible petunia. Plant Cell. 1990 Aug;2(8):815–826. doi: 10.1105/tpc.2.8.815. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Haring V., Gray J. E., McClure B. A., Anderson M. A., Clarke A. E. Self-incompatibility: a self-recognition system in plants. Science. 1990 Nov 16;250(4983):937–941. doi: 10.1126/science.2237440. [DOI] [PubMed] [Google Scholar]
- Horiuchi H., Yanai K., Takagi M., Yano K., Wakabayashi E., Sanda A., Mine S., Ohgi K., Irie M. Primary structure of a base non-specific ribonuclease from Rhizopus niveus. J Biochem. 1988 Mar;103(3):408–418. doi: 10.1093/oxfordjournals.jbchem.a122284. [DOI] [PubMed] [Google Scholar]
- Jahnen W., Batterham M. P., Clarke A. E., Moritz R. L., Simpson R. J. Identification, isolation, and N-terminal sequencing of style glycoproteins associated with self-incompatibility in Nicotiana alata. Plant Cell. 1989 May;1(5):493–499. doi: 10.1105/tpc.1.5.493. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Jahnen W., Lush W. M., Clarke A. E. Inhibition of in Vitro Pollen Tube Growth by Isolated S-Glycoproteins of Nicotiana alata. Plant Cell. 1989 May;1(5):501–510. doi: 10.1105/tpc.1.5.501. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Kawata Y., Sakiyama F., Tamaoki H. Amino-acid sequence of ribonuclease T2 from Aspergillus oryzae. Eur J Biochem. 1988 Oct 1;176(3):683–697. doi: 10.1111/j.1432-1033.1988.tb14331.x. [DOI] [PubMed] [Google Scholar]
- Laemmli U. K. Cleavage of structural proteins during the assembly of the head of bacteriophage T4. Nature. 1970 Aug 15;227(5259):680–685. doi: 10.1038/227680a0. [DOI] [PubMed] [Google Scholar]
- McClure B. A., Haring V., Ebert P. R., Anderson M. A., Simpson R. J., Sakiyama F., Clarke A. E. Style self-incompatibility gene products of Nicotiana alata are ribonucleases. Nature. 1989 Dec 21;342(6252):955–957. doi: 10.1038/342955a0. [DOI] [PubMed] [Google Scholar]
- Spurr A. R. A low-viscosity epoxy resin embedding medium for electron microscopy. J Ultrastruct Res. 1969 Jan;26(1):31–43. doi: 10.1016/s0022-5320(69)90033-1. [DOI] [PubMed] [Google Scholar]