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Query: UNIPROT:P06889 (Mol)
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In Brassica species, self-incompatibility has been mapped genetically to a single chromosomal location. In this region several closely linked genes have been identified. One of them, S-locus receptor kinase (SRK), determines S haplotype specificity of the stigma and it's the key protein for SI reaction. The role of the S locus glycoprotein (SLG) gene remains unclear. In the last decade approximately 15 additional genes linked to S-locus have been found. Recently, a gene has been identified (SCR) that encodes a small cysteine-rich protein which is a candidate for the pollen ligand. In addition to S locus linked genes there are unlinked SLRgenes (S-locus related genes). In this review, we discuss the role of these genes and the current view on the self-incompatibility mechanism in Brassica.
Curr Issues Mol Biol 2000 Oct
PMID:Molecular mechanisms of self-incompatibility in Brassica. 1147 54

Ovarian surface epithelial cells have been implicated in the genesis of common ovarian cancers. The integrity of DNA of ovarian surface epithelial cells contiguous with the ovulatory stigma becomes compromised during the rupture process; most cells degenerate by apoptosis, however some, bearing sublethal lesions, persist along the margins of ovulated follicles. Clonal expansion of a genetically-damaged surface epithelial cell (i.e. with unrepaired DNA, but not committed to death) can presumably give rise to ovarian carcinoma. It was hypothesized that estradiol and progesterone regulate ovarian surface epithelial cell-cycle dynamics associated with folliculo-luteal transitions and ovulatory wound repair/remodeling. Progesterone up-regulated the tumor suppressor p53 and inhibited baseline and estradiol-stimulated proliferation of cultured sheep ovarian surface epithelial cells. Anti/mitotic responses to steroid hormones were transcriptionally- and receptor-dependent. Rates of apoptosis (DNA fragmentation) were unaffected by progesterone. High concentrations of estradiol, via a nongenomic (perhaps antioxidant) mechanism, suppressed basal and H(2)O(2)-induced apoptosis. We suggest that, progesterone serves to inhibit proliferation of ovarian surface epithelial cells throughout the luteal phase--providing the time (growth arrest) required to correct any metabolic disturbances to DNA that are perpetrated as an inevitable by-product of the ovulatory process. With luteolysis and dominance of an estrogenic preovulatory follicle the ovarian surface epithelium is then regenerated. Thus, it is conceivable that perturbations to the steroid hormonal milieu of ovarian cycles could be a predisposing factor for cancerous transformation of an ovarian surface epithelial cell.
Mol Cell Endocrinol 2002 Jan 15
PMID:Steroid hormonal regulation of proliferative, p53 tumor suppressor, and apoptotic responses of sheep ovarian surface epithelial cells. 1185 Jan 22

Using differential screening we isolated a pistil-specific cDNA clone corresponding to a 1.2 kb mRNA and encoding a 32.5 kDa protein. The amino acid sequence shared similarity with that of group-I grass pollen allergens, which are known to have expansin activity. This clone, which later showed to share homology also with beta-expansins, was named PPAL. The PPAL mRNA was specifically expressed in the secretory zone of the stigma and in the epidermal layer of the placenta. The accumulation level of the transcript increased during pollination, and the protein was secreted in the stigmatic exudate of the tobacco flower. We suggest here that PPAL is a new expansin, acting as a cell-wall-loosening agent during pollination.
Plant Mol Biol 2002 May
PMID:Pollination modulates expression of the PPAL gene, a pistil-specific beta-expansin. 1199 74

The genomic clone encoding the pistil-specific thaumatin/PR5-like protein (PsTL1) was isolated from Japanese pear (Pyrus serotina). Sequence analysis showed that the genomic clone contained the 5'-flanking sequence of 2.4 kb, the 3'-flanking sequence of 648 bp and the coding region interrupted by a intron of 351 bp. A sequence motif conserved in some pistil self-incompatibility gene promoters of solanaceous and brassicaceous species was located in the 5'-flanking region of the PsTL1 gene. The 2.4 kb 5'-flanking region was fused to the GUS coding sequence and transferred to tobacco. Transgenic tobacco showed GUS activity in pistil and, at low level, in anther, but not in other floral organs and leaf. Histochemical analysis localized GUS activity to stigma, transmitting tissue, anther and pollen of transgenic tobacco.
Plant Mol Biol 2002 Oct
PMID:A pistil-specific thaumatin/PR5-like protein gene of Japanese pear (Pyrus serotina): sequence and promoter activity of the 5' region in transgenic tobacco. 1236 14

During pollination the pollen tube grows into the style and toward the ovary via the transmitting tract. In lily the growth of pollen tubes involves tube cell adhesion to transmitting tract cells. We reported two molecules involved in this adhesion event. One is a pectic polysaccharide and the other, a 9 kDa basic protein named SCA for stigma/stylar cysteine-rich adhesin. SCA, which shows some identity with LTP (lipid transfer protein), was localized to the transmitting tract epidermis of the style where pollen tubes adhere. The present studies on the expression of SCA indicate that the protein has a similar expression pattern with LTP1 in Arabidopsis and that the protein is abundant in both the stigma and the style. For further proof of its role in pollen tube adhesion the activity of Escherichia coli-expressed protein has been studied in an in vitro adhesion assay system.
Plant Mol Biol 2003 Jan
PMID:Expression studies of SCA in lily and confirmation of its role in pollen tube adhesion. 1260 77

Microspores at late uninucleate/early binucleate stages were isolated from flower buds of tobacco (Nicotiana tabacum L.) and in vitro culture methods optimised for their maturation to fully functional viable pollen which, after application to the stigma of emasculated plants in situ, led to the generation of large numbers of seed. Efficient protocols were established for the biolistic introduction of a construct containing a reporter gene and selectable marker into these microspores and hence, after in vitro maturation and in situ fertilisation, for the generation of transgenic plants. Stable transformants of low copy number were generated by this procedure. The efficiency of transformation achieved allows the production of large numbers of transgenic plants without selection, dispensing with the requirement for a selectable marker in plant transgenesis.
Plant Mol Biol 2003 Jan
PMID:Efficient male germ line transformation for transgenic tobacco production without selection. 1260 79

We have identified several interspecific pairs of S haplotypes having highly similar SRK and SP11/SCR sequences between Brassica oleracea and Brassica rapa. The recognition specificities of S haplotypes in these pairs were examined with three different methods. Stigmas of interspecific hybrids between an S-32 homozygote in B. oleracea and an S-60 homozygote in B. rapa, which were produced to avoid the interspecific incompatibility between the two species, showed incompatibility to the pollen of an S-8 homozygote in B. rapa and to the pollen of an S-15 homozygote in B. oleracea, while it showed compatibility to the pollen of other S haplotypes, suggesting B. oleracea S-32 and B. rapa S-60 have the same recognition specificity as B. rapa S-8 and B. oleracea S-15. Pollen grains of transgenic S-60 homozygous plants in B. rapa carrying a transgene of SP11-24 from B. oleracea were incompatible to B. rapa S-36 stigma, indicating that B. oleracea S-24 and B. rapa S-36 have the same recognition specificity. Application of the SP11 protein of B. rapa S-41 and S-47 onto the surface of B. oleracea S-64 stigmas and S-12 stigmas, respectively, resulted in the incompatibility reaction to pollen grains of another S haplotype, but application onto the stigmas of other S haplotypes did not, suggesting that B. oleracea S-64 stigmas and S-12 stigmas recognized the B. rapa SP11-41 and SP11-47 proteins as self SP11 proteins, respectively. Besides having evolutionary implications, finding of many interspecific pairs of S haplotypes can provide insight into the molecular mechanism of self-recognition. Comparing deduced amino-acid sequences of SP11 proteins and SRK proteins in the pairs, regions of SP11 and SRK important for self-recognition are discussed.
Plant Mol Biol 2003 Jun
PMID:Commonality of self-recognition specificity of S haplotypes between Brassica oleracea and Brassica rapa. 1295 31

We have isolated a cDNA clone, OsFOR1, from the immature panicles of rice. The OsFOR1 (Oryza sativa floral organ regulator 1) gene encodes a protein that contains a leucine-rich repeat (LRR) domain. This domain comprises 10 tandem repeats of a canonical 24-amino acid LRR sequence. The structure and the number of LRRs for OsFOR1 are similar to those of polygalacturonase-inhibiting proteins (PGIPs) from various other plant species. Moreover, the OsFOR1 recombinant protein, when fused to maltose-binding protein (MBP), shows PGIP activity against the Aspergillus niger polygalacturonase. OsFOR1 is highly expressed in the calli and immature and mature panicles, while detectable at only low levels in seedling roots and mature stems. In situ hybridization experiments showed the transcripts of OsFOR1 are present in young spikelet primordia and in almost all of the young floral organs. Transgenic approaches were used to study in vivo functioning. Antisense expression of OsFOR1 resulted in an increase in the numbers of floral organs, including the stamen, carpel, palea/lemma, stigma, and lodicule. OsFOR1 transcript was not detected in the frizzy panicle mutant, which is defective in its spikelet formation but normal in inflorescence-meristem initiation and maintenance. Therefore, we suggest that OsFOR1 plays a role in the formation and/or maintenance of floral organ primordia.
Plant Mol Biol 2003 Oct
PMID:The OsFOR1 gene encodes a polygalacturonase-inhibiting protein (PGIP) that regulates floral organ number in rice. 1475 May 24

Pollination regulates a syndrome of developmental responses that contributes to successful sexual reproduction in higher plants. Pollination-regulated developmental events collectively prepare the flower for fertilization and embryogenesis while bringing about the loss of floral organs that have completed their function in pollen dispersal and reception. Components of this process include changes in flower pigmentation, senescence and abscission of floral organs, growth and development of the ovary, and, in certain cases, pollination also triggers ovule and female gametophyte development in anticipation of fertilization. Pollination-regulated development is initiated by the primary pollination event at the stigma surface, but because developmental processes occur in distal floral organs, the activity of interorgan signals that amplify and transmit the primary pollination signal to floral organs is implicated. Interorgan signaling and signal amplification involves the regulation of ethylene biosynthetic gene expression and interorgan transport of hormones and their precursors. The coordination of pollination- regulated flower development including gametophyte, embryo, and ovary development; pollination signaling; the molecular regulation of ethylene biosynthesis; and interorgan communication are presented.
Annu Rev Plant Physiol Plant Mol Biol 1997 Jun
PMID:POLLINATION REGULATION OF FLOWER DEVELOPMENT. 1501 74

In Brassica , the thioredoxin h proteins, THL1 and THL2, were previously found to be potential inhibitors of the S receptor kinase (SRK) in the Brassica self-incompatibility response. To investigate the biological roles of THL1 and THL2 in pollen-pistil interactions, the stigma-specific SLR1 promoter was used to drive antisense THL1/2 expression in Brassica napus cv. Westar. This cultivar is normally compatible, but antisense suppression of THL1/2 led to a low level constitutive rejection of all Brassica napus pollen tested. Fluorescence microscopy revealed that the pollen rejection was a typical Brassica self-incompatibility rejection response with reduced pollen adhesion, germination and pollen tube growth. In addition, Westar was found to express the SLG(15) and SRK(15) proteins which may be the target of regulation by THL1 and THL2. Thus, these results indicate that the THL1 and THL2 are required for full pollen acceptance in B. napus cv. Westar.
Plant Mol Biol 2004 Jul
PMID:Antisense suppression of thioredoxin h mRNA in Brassica napus cv. Westar pistils causes a low level constitutive pollen rejection response. 1560 5


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