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Plant Cell. Jan 1995; 7(1): 65–74.
PMCID: PMC160765

The Significance of Microspore Division and Division Symmetry for Vegetative Cell-Specific Transcription and Generative Cell Differentiation.


The significance of the onset and symmetry of pollen mitosis I (PMI) for the subsequent differentiation of the vegetative and generative cells was investigated by the in vitro maturation of isolated microspores of transgenic tobacco. Free uninucleate microspores of transgenic plants harboring the vegetative cell (VC)-specific late anther tomato lat52 promoter fused to the [beta]-glucuronidase (gus) gene showed normal asymmetric cell division at PMI and activated the lat52 promoter specifically in the nascent VC during in vitro maturation. In vitro maturation in the presence of high levels of colchicine effectively blocked PMI, resulting in the formation of uninucleate pollen grains in which the lat52 promoter was activated. Furthermore, matured uninucleate pollen grains were capable of germination and pollen tube growth despite the absence of a functional generative cell (GC). Lower levels of colchicine induced symmetric division at PMI, producing two similar daughter cells in which typical GC chromatin condensation was prevented. Similar cultures of transgenic microspores harboring the lat52 promoter driving the expression of a nuclear-targeted GUS fusion protein showed that lat52 promoter activation occurred in both symmetric daughter cells. These results directly demonstrate that division asymmetry at PMI is essential for correct GC differentiation and that activation of VC-specific transcription and functional VC maturation may be uncoupled from cytokinesis at PMI. These results are discussed in relation to models proposed to account for the role and distribution of factors controlling the differing fates of the vegetative and generative cells.

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Selected References

These references are in PubMed. This may not be the complete list of references from this article.
  • Heslop-Harrison J, Heslop-Harrison Y. Evaluation of pollen viability by enzymatically induced fluorescence; intracellular hydrolysis of fluorescein diacetate. Stain Technol. 1970 May;45(3):115–120. [PubMed]
  • Horvitz HR, Herskowitz I. Mechanisms of asymmetric cell division: two Bs or not two Bs, that is the question. Cell. 1992 Jan 24;68(2):237–255. [PubMed]
  • Muschietti J, Dircks L, Vancanneyt G, McCormick S. LAT52 protein is essential for tomato pollen development: pollen expressing antisense LAT52 RNA hydrates and germinates abnormally and cannot achieve fertilization. Plant J. 1994 Sep;6(3):321–338. [PubMed]
  • Twell D, Yamaguchi J, McCormick S. Pollen-specific gene expression in transgenic plants: coordinate regulation of two different tomato gene promoters during microsporogenesis. Development. 1990 Jul;109(3):705–713. [PubMed]
  • Way JC, Chalfie M. The mec-3 gene of Caenorhabditis elegans requires its own product for maintained expression and is expressed in three neuronal cell types. Genes Dev. 1989 Dec;3(12A):1823–1833. [PubMed]
  • Way JC, Wang L, Run JQ, Wang A. The mec-3 gene contains cis-acting elements mediating positive and negative regulation in cells produced by asymmetric cell division in Caenorhabditis elegans. Genes Dev. 1991 Dec;5(12A):2199–2211. [PubMed]

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