Gene Expression In Buds Research Articles

Strigolactones and Cytokinin Interaction in Buds in the Control of Rice Tillering.

Shoot branching is among the most crucial morphological traits in rice (Oryza sativa L.) and is physiologically modulated by auxins, cytokinins (CKs), and strigolactones (SLs) cumulatively in rice. A number of studies focused on the interplay of these three hormones in regulating rice tiller extension. The present study primarily aimed at determining the impact of different treatments, which were used to regulate rice tiller and axillary bud development on node 2 at the tillering stage and full heading stage, respectively. Transcription levels of several genes were quantified through qRT-PCR analysis, and an endogenous auxin and four types of CKs were determined through LC-MS/MS. Both nutrient deficiency and exogenous SL supply were found to inhibit rice tiller outgrowth by reducing the CK content in the tiller buds. Furthermore, supplying the inhibitor of both exogenous SLs and endogenous SL synthesis could also affect the expression level of OsCKX genes but not the OsIPT genes. Comparison of OsCKX gene expression pattern under exogenous SL and CK supply suggested that the induction of OsCKX expression was most likely via a CK-induced independent pathway. These results combined with the expression of CK type-A RR genes in bud support a role for SLs in regulating bud outgrowth through the regulation of local CK levels. SL functioned antagonistically with CK in regulating the outgrowth of buds on node 2, by promoting the OsCKX gene expression in buds.

Proteomic analysis of axillary buds of sugarcane at different cutting stages: evidence for alterations in axillary bud gene expression

Productivity of sugarcane (Saccharum spp.) crops varies at each cutting stage, reaching critical rates close to the fifth cut (fourth ratoon). Knowledge of proteins involved in the regrowth of sugarcane within the cutting process is important for the development of cultivars with greater longevity. The present study presents new information that the proteome of axillary buds is changed in successive cuts in sugarcane culture. Proteins were identified by UPLC-ESI-Q-TOF (ultra-high-performance liquid chromatography coupled with electrospray ionisation–quadrupole–time-of-flight) mass spectrometry and the Mascot tool. A reduction in the number of proteins was evident in the axillary buds of the fifth cut, as well as a reduction in the number of proteins exclusively detected in the axillary buds with the first cut, an indicator of reduction in the expression of genes that may be essential for the stability of culture development. The reduction in agricultural productivity, sprouting and tillering at advanced stages of the sugarcane crop is accompanied by alterations in axillary-bud gene expression, where <50% of the proteins (47.65%) were detected in both the first (plant cane) and in the fifth (fourth ratoon) cutting stage, whereas >50% (52.35%) were expressed in either the axillary buds of the plant cane or the axillary buds of the fourth ratoon. All MS data are available via jPOST and ProteomeXchange with identifiers JPST000331 and PXD007957, respectively.

No detriment in taste response or expression in offspring of mice fed representative levels of sucrose or non-caloric sucralose while pregnant

Recent studies in mice indicate that consumption of acesulfame K (a high intensity sweetener) while pregnant, can lead to deficits in taste or enhanced sweet consumption in the offspring, leading to concerns the same may be common in human populations. However, this work employed a relatively unpopular sweetener, fed in quantities amounting to over 20× the FDA's Acceptable Daily Intake (ADI). The aims of this study were to test the effects of sucralose, the USA's most popular high intensity sweetener, along with sucrose, on the taste system of the offspring of mice supplemented at a level commensurate with ADIs while pregnant. The hypothesis was that feeding a dam intensely sweet solutions would produce offspring with enhanced response to sweet taste, when compared to offspring of dams given only water. Females were mated following a 4-week period in which one group was given a measured ration of sucrose or sucralose in addition to chow and water, with the control group given chow and water only. Sucrose and sucralose solutions were removed two weeks after parturition to prevent direct consumption by the offspring. The offspring at 8weeks of age for both the sucrose and sucralose supplementation showed no change in their taste response to sucrose or sucralose. No effect of maternal sweet supplementation was detected at the taste bud level, with fungiform taste bud density and taste bud gene expression remaining unchanged. Overall, this study suggests that sucrose and sucralose consumption at human-relevant levels during pregnancy and lactation do not produce any long-term changes to the offspring's peripheral taste system.

Fruit load modulates flowering-related gene expression in buds of alternate-bearing 'Moncada' mandarin.

Gene determination of flowering is the result of complex interactions involving both promoters and inhibitors. In this study, the expression of flowering-related genes at the meristem level in alternate-bearing citrus trees is analysed, together with the interplay between buds and leaves in the determination of flowering. First defruiting experiments were performed to manipulate blossoming intensity in 'Moncada' mandarin, Citrus clementina. Further defoliation was performed to elucidate the role leaves play in the flowering process. In both cases, the activity of flowering-related genes was investigated at the flower induction (November) and differentiation (February) stages. Study of the expression pattern of flowering-genes in buds from on (fully loaded) and off (without fruits) trees revealed that homologues of FLOWERING LOCUS T (CiFT), TWIN SISTER OF FT (TSF), APETALA1 (CsAP1) and LEAFY (CsLFY) were negatively affected by fruit load. CiFT and TSF activities showed a marked increase in buds from off trees through the study period (ten-fold in November). By contrast, expression of the homologues of the flowering inhibitors of TERMINAL FLOWER 1 (CsTFL), TERMINAL FLOWER 2 (TFL2) and FLOWERING LOCUS C (FLC) was generally lower in off trees. Regarding floral identity genes, the increase in CsAP1 expression in off trees was much greater in buds than in leaves, and significant variations in CsLFY expression (approx. 20 %) were found only in February. Defoliation experiments further revealed that the absence of leaves completely abolished blossoming and severely affected the expression of most of the flowering-related genes, particularly decreasing the activity of floral promoters and of CsAP1 at the induction stage. These results suggest that the presence of fruit affects flowering by greatly altering gene-expression not only at the leaf but also at the meristem level. Although leaves are required for flowering to occur, their absence strongly affects the activity of floral promoters and identity genes.

Visualization and quantification of mouse prostate development by in situ hybridization

The purpose of this study was to validate a combined in situ hybridization (ISH)/immunohistochemistry (IHC) staining method for visualizing and quantifying mouse prostatic buds. To refine animal usage in prostate development studies, we also determined whether a comparable number of prostatic buds were formed in male and female mouse urogenital sinus (UGS) explants grown in vitro in the presence of androgen. We used IHC to label UGS epithelium and ISH to label prostatic buds with one of three different prostatic bud marking riboprobes: a previously identified prostatic bud marker, NK-3 transcription factor, locus 1 (Nkx3-1), and two newly identified prostatic bud markers, wingless-related MMTV integration site 10b (Wnt10b) and ectodysplasin-A receptor (Edar). We calculated total buds formed per UGS and the proportion marked by each mRNA after male UGS development in vivo and male and female UGS development in vitro. Nkx3-1 was first to mark the prostate field during UGS development in vivo but all three mRNAs marked prostatic buds during later developmental stages. The mRNAs localized to different domains: Nkx3-1 was present along about half the prostatic bud length while Edar and Wnt10b were restricted to distal bud tips. None of the mRNAs marked all buds formed in vitro and the proportion marked was developmental stage- and gender-dependent. Nkx3-1 marked the highest proportion of prostatic buds during in vitro UGS development. Together, our results reveal that ISH staining of mouse UGS can be used to quantify prostatic bud number, Nkx3-1 is currently the best suited riboprobe for this method, and female UGSs cannot be used interchangeably with male UGSs when conducting prostate development studies in vitro. We also found that Nkx3-1, Edar, and Wnt10b mark different prostatic bud regions and are likely to be useful in future studies of regional differences in prostatic bud gene expression.

Squeezing into Differentiation

The earliest steps in tooth development depend on signaling interactions that result in the condensation of mandibular mesenchyme into the tooth bud. Reporting in this issue of Developmental Cell, Mammoto et al. (2011) find that chemotactic signals coordinate condensation and that the compressive force generated is sufficient to induce tooth bud gene expression.

Genome-Wide Analysis of Gene Expression in Primate Taste Buds Reveals Links to Diverse Processes

Efforts to unravel the mechanisms underlying taste sensation (gustation) have largely focused on rodents. Here we present the first comprehensive characterization of gene expression in primate taste buds. Our findings reveal unique new insights into the biology of taste buds. We generated a taste bud gene expression database using laser capture microdissection (LCM) procured fungiform (FG) and circumvallate (CV) taste buds from primates. We also used LCM to collect the top and bottom portions of CV taste buds. Affymetrix genome wide arrays were used to analyze gene expression in all samples. Known taste receptors are preferentially expressed in the top portion of taste buds. Genes associated with the cell cycle and stem cells are preferentially expressed in the bottom portion of taste buds, suggesting that precursor cells are located there. Several chemokines including CXCL14 and CXCL8 are among the highest expressed genes in taste buds, indicating that immune system related processes are active in taste buds. Several genes expressed specifically in endocrine glands including growth hormone releasing hormone and its receptor are also strongly expressed in taste buds, suggesting a link between metabolism and taste. Cell type-specific expression of transcription factors and signaling molecules involved in cell fate, including KIT, reveals the taste bud as an active site of cell regeneration, differentiation, and development. IKBKAP, a gene mutated in familial dysautonomia, a disease that results in loss of taste buds, is expressed in taste cells that communicate with afferent nerve fibers via synaptic transmission. This database highlights the power of LCM coupled with transcriptional profiling to dissect the molecular composition of normal tissues, represents the most comprehensive molecular analysis of primate taste buds to date, and provides a foundation for further studies in diverse aspects of taste biology.

Relative developmental, environmental, and tree-to-tree variability in buds from field-grown apple trees

High-throughput genomic technologies are becoming more accessible to nonmodel plant species, and therefore, tissue collected outside controlled environments is being increasingly used for microarray analyses. In this study, we present a 15,720-feature apple microarray analysis of the variability of gene expression in buds from field-grown apple trees. Tree-to-tree and day-to-day variances were assessed during two different seasons: summer, when the meristems in the buds were undergoing the first stages of floral development, and autumn, when the buds were undergoing transition to winter dormancy. We found that apple trees with the same scion and rootstock cultivars, grown in a standard orchard environment, had small tree-to-tree variation. Gene expression differences caused by season was the dominant cause of variance while using false discovery rate control with a threshold of α* = 0.01 to select significantly different expression between genes. At this threshold, the environmental and location effects accounted for less than 10% of the genes selected. Consequently, we have shown that field microarray experiments are a viable approach for measuring seasonal changes in gene expression during apple bud development.

EGF Signaling Patterns the Feather Array by Promoting the Interbud Fate

Feather buds form sequentially in a hexagonal array. Bone morphogenetic protein (BMP) signaling from the feather bud inhibits bud formation in the adjacent interbud tissue, but whether interbud fate and patterning is actively promoted by BMP or other factors is unclear. We show that epidermal growth factor (EGF) signaling acts positively to establish interbud identity. EGF and the active EGF receptor (EGFR) are expressed in the interbud regions. Exogenous EGF stimulates epidermal proliferation and expands interbud gene expression, with a concurrent loss of feather bud gene expression and morphology. Conversely, EGFR inhibitors result in the loss of interbud fate and increased acquisition of feather bud fate. EGF signaling acts directly on the epidermis and is independent of BMP signaling. The timing of competence to interpret interbud-promoting signals occurs at an earlier developmental stage than previously anticipated. These data demonstrate that EGFR signaling actively promotes interbud identity.