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81.
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SCB1, a BURP-domain protein gene,from developing soybean seed coats   总被引:1,自引:0,他引:1  
We describe a gene, SCB1 (Seed Coat BURP-domain protein 1), that is expressed specifically within the soybean (Glycine max [L.] Merrill) seed coat early in its development. Northern blot analysis and mRNA in situ hybridization revealed novel patterns of gene expression during seed development. SCB1 mRNA accumulated first within the developing thick-walled parenchyma cells of the inner integument and later in the thick- and thin-walled parenchyma cells of the outer integument. This occurred prior to the period of seed coat maturation and seed filling and before either of the layers started to degrade. SCB1 may therefore play a role in the differentiation of the seed coat parenchyma cells. In addition, the protein product appears to be located within cell walls. The SCB1 gene codes for a new member of a class of modular proteins that possess a carboxy-terminal BURP domain and a variety of different repeated sequences. The sequence of the genomic clone revealed the insertion of a Tgm transposable element in the upstream promoter region but it is not certain whether it contributes to the tissue-specific pattern of SCB1 expression.  相似文献   
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Intracellular type I platelet activating factor-acetylhydrolase is a phospholipase that consists of a dimer of two homologous catalytic subunits alpha1 and alpha2 as well as LIS1, a product of the causative gene for type I lissencephaly. LIS1 plays an important role in neuronal migration during brain development, but the in vivo function of the catalytic subunits remains unclear. In this study, we generated alpha1- and a2-deficient mice by targeted disruption. alpha1(-/-) mice are indistinguishable from wild-type mice, whereas alpha2(-/-) male mice show a significant reduction in testis size. Double-mutant male mice are sterile because of severe impairment of spermatogenesis. Histological examination revealed marked degeneration at the spermatocyte stage and an increase of apoptotic cells in the seminiferous tubules. The catalytic subunits are expressed at high levels in testis as well as brain in mice. In wild-type mice, alpha2 is expressed in all seminiferous tubule cell types, whereas alpha1 is expressed only in the spermatogonia. This expression pattern parallels the finding that deletion of both subunits induces a marked loss of germ cells at an early spermatogenic stage. We also found that the LIS1 protein levels, but not the mRNA levels, were significantly reduced in alpha2(-/-) and double-mutant mice, suggesting that the catalytic subunits, especially alpha2, are a determinant of LIS1 expression level.  相似文献   
86.
Herein, we report a unique technique to accelerate polymer-SNA conjugation based on copper-free click chemistry: gradual freeze-thawing of the reaction solution substantially increases the conjugation rate possibly because of the reactant concentration at the microenvironment scale. This technique was applied to the conjugation between a small interfering RNA (siRNA) and PEG in an aqueous buffer at/below room temperature.  相似文献   
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When skin fibroblasts were cultured on fibrillar collagen I gel, we observed rapid degradation of talin, fodrin and ezrin, which are well-known calpain substrates. The protease m-calpain was activated only in cells adhering to fibrillar collagen, whereas micro-calpain was activated in cells adhering to monomeric or fibrillar collagen at the same level. The calpain inhibitor Z-Leu-Leu-aldehyde inhibited degradation of fodrin, but not talin. Degradation of fodrin, alpha-actinin and ezrin was prevented by over-expression of dominant negative m-calpain. However, over-expression of calpastatin, an endogenous calpain inhibitor, had no effect the degradation of these three proteins. These results suggest that m-calpain is responsible for degradation of their membrane proteins via adhesion to fibrillar collagen I gel.  相似文献   
89.
p‐Coumaroyl ester 3‐hydroxylase (C3′H) is a key enzyme involved in the biosynthesis of lignin, a phenylpropanoid polymer that is the major constituent of secondary cell walls in vascular plants. Although the crucial role of C3′H in lignification and its manipulation to upgrade lignocellulose have been investigated in eudicots, limited information is available in monocotyledonous grass species, despite their potential as biomass feedstocks. Here we address the pronounced impacts of C3H deficiency on the structure and properties of grass cell walls. C3H‐knockdown lines generated via RNA interference (RNAi)‐mediated gene silencing, with about 0.5% of the residual expression levels, reached maturity and set seeds. In contrast, C3H‐knockout rice mutants generated via CRISPR/Cas9‐mediated mutagenesis were severely dwarfed and sterile. Cell wall analysis of the mature C3H‐knockdown RNAi lines revealed that their lignins were largely enriched in p‐hydroxyphenyl (H) units while being substantially reduced in the normally dominant guaiacyl (G) and syringyl (S) units. Interestingly, however, the enrichment of H units was limited to within the non‐acylated lignin units, with grass‐specific γ‐p‐coumaroylated lignin units remaining apparently unchanged. Suppression of C3H also resulted in relative augmentation in tricin residues in lignin as well as a substantial reduction in wall cross‐linking ferulates. Collectively, our data demonstrate that C3H expression is an important determinant not only of lignin content and composition but also of the degree of cell wall cross‐linking. We also demonstrated that C3H‐suppressed rice displays enhanced biomass saccharification.  相似文献   
90.
In Arabidopsis thaliana the ANGUSTIFOLIA (AN) gene regulates the width of leaves by controlling the diffuse growth of leaf cells in the medio‐lateral direction. In the genome of the moss Physcomitrella patens, we found two normal ANs (PpAN1‐1 and 1‐2). Both PpAN1 genes complemented the A. thaliana an‐1 mutant phenotypes. An analysis of spatiotemporal promoter activity of each PpAN1 gene, using transgenic lines that contained each PpAN1‐promoter– uidA (GUS) gene, showed that both promoters are mainly active in the stems of haploid gametophores and in the middle to basal region of the young sporophyte that develops into the seta and foot. Analyses of the knockout lines for PpAN1‐1 and PpAN1‐2 genes suggested that these genes have partially redundant functions and regulate gametophore height by controlling diffuse cell growth in gametophore stems. In addition, the seta and foot were shorter and thicker in diploid sporophytes, suggesting that cell elongation was reduced in the longitudinal direction, whereas no defects were detected in tip‐growing protonemata. These results indicate that both PpAN1 genes in P. patens function in diffuse growth of the haploid and diploid generations but not in tip growth. To visualize microtubule distribution in gametophore cells of P. patens, transformed lines expressing P. patens α‐tubulin fused to sGFP were generated. Contrary to expectations, the orientation of microtubules in the tips of gametophores in the PpAN1‐1/1‐2 double‐knockout lines was unchanged. The relationships among diffuse cell growth, cortical microtubules and AN proteins are discussed.  相似文献   
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