Molecular Mechanisms of Pollen Tube Growth and Differentiation

Mascarenhas, Joseph P.

doi:10.2307/3869783

Cited by 150 publications

(104 citation statements)

References 71 publications

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“…The pollenspecific expression of ZmABPJ and ZmABP2 is similar to that previously observed for three maize profilin genes (3). Moreover, the ZmABP1 and ZmABP2 genes now join the relatively small group of proteins active in the male gametophyte but not in the sporophyte (48).…”

Section: Discussionmentioning

confidence: 99%

Pollen specific expression of maize genes encoding actin depolymerizing factor-like proteins.

López

Anthony

Maciver

et al. 1996

Proc. Natl. Acad. Sci. U.S.A.

130

135

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In pollen development, a dramatic reorganization of the actin cytoskeleton takes place during the passage of the pollen grain into dormancy and on activation of pollen tube growth. A identical to ZmABPI and ZmABP2, respectively, and its expression is suppressed in pollen and germinated pollen. The fundamental biochemical characteristics of the ZmABP proteins has been elucidated using bacterially expressed ZmABP3 protein. This has the ability to bind monomeric actin (G-actin) and filamentous actin (F-actin). Moreover, it decreases the viscosity of polymerized actin solutions consistent with an ability to depolymerize filaments. These biochemical characteristics, taken together with the sequence comparisons, support the inclusion of the ZmABP proteins in the ADF group.

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Section: Discussionmentioning

confidence: 99%

Pollen specific expression of maize genes encoding actin depolymerizing factor-like proteins.

López

Anthony

Maciver

et al. 1996

Proc. Natl. Acad. Sci. U.S.A.

130

135

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“…[1][2][3]. The pollen produces a tube that penetrates the stigma and grows through the wall of adjacent cells in the transmitting track in the style to reach the ovary, where the tube delivers the male gametes to fertilize the eggs.…”

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confidence: 99%

“…It includes an outermost coat and an underlying wall (1)(2)(3). The coat consists of lipids and proteins, which are initially synthesized and accumulated in the tapetum cells that enclose the pollen locule in the anthers.…”

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confidence: 99%

Cell Wall Reactive Proteins in the Coat and Wall of Maize Pollen

Suen

Chang

et al. 2003

Journal of Biological Chemistry

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The surface of a pollen grain consists of an outermost coat and an underlying wall. In maize (Zea mays L.), the pollen coat contains two major proteins derived from the adjacent tapetum cells in the anthers. One of the proteins is a 35-kDa endoxylanase (Wu, S. S. H., Suen, D. F., Chang, H. C., and Huang, A. H. C. (2002) J. Biol. Chem. 277, 49055-49064). The other protein of 70 kDa was purified to homogeneity and shown to be a ␤-glucanase. Its gene sequence and the developmental pattern of its mRNA differ from those of the known ␤-glucanases that hydrolyze the callose wall of the microspore tetrad. Mature pollen placed in a liquid medium released about nine major proteins. These proteins were partially sequenced and identified via GenBank TM data bases, and some had not been previously reported to be in pollen. They appear to have wall-loosening, structural, and enzymatic functions. A novel pollen wall-bound protein of 17 kDa has a unique pattern of cysteine distribution in its sequence (six tandem repeats of CX 3 CX 10 -15 ) that could chelate cations and form signal-receiving finger motifs. These pollen-released proteins were synthesized in the pollen interior, and their mRNA increased during pollen maturation and germination. They were localized mainly in the pollen tube wall. The pollen shell was isolated and found to contain no detectable proteins. We suggest that the pollen-coat ␤-glucanase and xylanase hydrolyze the stigma wall for pollen tube entry and that the pollen secrete proteins to loosen or become new wall constituents of the tube and to break the wall of the transmitting track for tube advance.In plants, sexual reproduction is initiated when the pollen grain (male component) lands on the stigma of the style (female component) in the flowers (for reviews, see Refs.

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“…Therefore, it seems likely that pollen also contains HRGPs. These extracellular proteins may play a structural role in the extremely rapid cell elongation that occurs during pollen tube growth (12). Alternatively, pollen HRGPs are potential candidates for mediating pollen-pistil interactions in conjunction with partner molecules in female tissues.…”

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confidence: 99%

Pex1, a pollen-specific gene with an extensin-like domain.

Rubinstein

Broadwater

Lowrey

et al. 1995

Proc. Natl. Acad. Sci. U.S.A.

105

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We report here the identification of a pollenspecific gene from Zea mays that contains multiple Ser-(Pro).repeats, the motif found in the cell wall-associated extensins.Sequence analysis reveals that the encoded protein has a putative globular domain at the N terminus and an extensinlike domain at the C terminus. (3)(4)(5)(6). In addition, stylar tissues are known to secrete AGPs (7). It is known that pollen is enriched for hydroxyproline (8-11). Therefore, it seems likely that pollen also contains HRGPs. These extracellular proteins may play a structural role in the extremely rapid cell elongation that occurs during pollen tube growth (12). Alternatively, pollen HRGPs are potential candidates for mediating pollen-pistil interactions in conjunction with partner molecules in female tissues. We have isolated a pollen-specific gene that appears to be a member of a small gene family in maize and encodes multiple repeats of the extensin-like motif Ser-(Pro)4. Pexl (pollen extensin-like) differs from other maize HRGP genes in that it contains significant numbers of this canonical extensin repeat motif. Isolation of a genomic clone representing the Pexi gene revealed a protein structure containing both an extensin-like domain and a putative globular domain.J MATERIALS AND METHODS Maize inbred lines Ky2l and B73 were grown under standard greenhouse conditions. Microspores and immature pollen were staged by the method of Bedinger and Edgerton (13). Mature pollen was collected from shedding tassels. Young leaves were wounded by clamping with a hemostat and were collected 6 and 24 hr after wounding.The publication costs of this article were defrayed in part by page charge payment. This article must therefore be hereby marked "advertisement" in accordance with 18 U.S.C. §1734 solely to indicate this fact. pSF66 and pSF21 were isolated from a cDNA library prepared from poly(A)+ RNA from immature starch-filled pollen (maize inbred line Ky2l) and cloned into AZAP (Stratagene) with EcoRI-Not I adapters (Invitrogen). Recombinant phage were differentially screened with cDNA probes made by using mRNA from immature starch-filled pollen and from endosperm. Plaques that hybridized uniquely with immature pollen mRNA were selected and rescreened.A genomic library prepared from Sau3A1 partial digests of maize inbred line B73 DNA cloned into phage AEMBL3 arms was purchased from Clontech. In all, 240,000 plaques, representing half a genome of DNA, were screened with pSF21 cDNA as a probe. Two positive clones were identified. One of these was subcloned into pBluescript (Stratagene).A 7.3-kb BamHI subclone containing sequences hybridizing to pSF21 was designated pZmPl. Four thousand three hundred thirty-one base pairs of pZmPl were sequenced by the dideoxy method (14) using Sequenase (United States Biochemical) and [a-32P]dATP (Amersham). Sequences of pZmPl were confirmed by the University of North Carolina, Chapel Hill, Automated DNA Sequencing Facility on a model 373A DNA sequencer using the Taq DyeDeoxy terminator cycle sequenci...

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Molecular Mechanisms of Pollen Tube Growth and Differentiation

Cited by 150 publications

References 71 publications

Pollen specific expression of maize genes encoding actin depolymerizing factor-like proteins.

Pollen specific expression of maize genes encoding actin depolymerizing factor-like proteins.

Cell Wall Reactive Proteins in the Coat and Wall of Maize Pollen

Pex1, a pollen-specific gene with an extensin-like domain.

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