Bud Morphogenesis Research Articles

Study of impacts of two types of cellular aging on the yeast bud morphogenesis.

Understanding the mechanisms of the cellular aging processes is crucial for attempting to extend organismal lifespan and for studying age-related degenerative diseases. Yeast cells divide through budding, providing a classical biological model for studying cellular aging. With their powerful genetics, relatively short cell cycle, and well-established signaling pathways also found in animals, yeast cells offer valuable insights into the aging process. Recent experiments suggested the existence of two aging modes in yeast characterized by nucleolar and mitochondrial declines, respectively. By analyzing experimental data, this study shows that cells evolving into those two aging modes behave differently when they are young. While buds grow linearly in both modes, cells that consistently generate spherical buds throughout their lifespan demonstrate greater efficacy in controlling bud size and growth rate at young ages. A three-dimensional multiscale chemical-mechanical model was developed and used to suggest and test hypothesized impacts of aging on bud morphogenesis. Experimentally calibrated model simulations showed that during the early stage of budding, tubular bud shape in one aging mode could be generated by locally inserting new materials at the bud tip, a process guided by the polarized Cdc42 signal. Furthermore, the aspect ratio of the tubular bud could be stabilized during the late stage as observed in experiments in this work. The model simulation results suggest that the localization of new cell surface material insertion, regulated by chemical signal polarization, could be weakened due to cellular aging in yeast and other cell types, leading to the change and stabilization of the bud aspect ratio.

Photo-induced changes in tissue stiffness alter epithelial budding morphogenesis in the embryonic lung.

Extracellular matrix (ECM) stiffness has been shown to influence the differentiation of progenitor cells in culture, but a lack of tools to perturb the mechanical properties within intact embryonic organs has made it difficult to determine how changes in tissue stiffness influence organ patterning and morphogenesis. Photocrosslinking of the ECM has been successfully used to stiffen soft tissues, such as the cornea and skin, which are optically accessible, but this technique has not yet been applied to developing embryos. Here, we use photocrosslinking with Rose Bengal (RB) to locally and ectopically stiffen the pulmonary mesenchyme of explanted embryonic lungs cultured ex vivo . This change in mechanical properties was sufficient to suppress FGF-10-mediated budding morphogenesis along the embryonic airway, without negatively impacting patterns of cell proliferation or apoptosis. A computational model of airway branching was used to determine that FGF-10-induced buds form via a growth-induced buckling mechanism and that increased mesenchymal stiffness is sufficient to inhibit epithelial buckling. Taken together, our data demonstrate that photocrosslinking can be used to create regional differences in mechanical properties within intact embryonic organs and that these differences influence epithelial morphogenesis and patterning. Further, this photocrosslinking assay can be readily adapted to other developing tissues and model systems.

PDX1+ cell budding morphogenesis in a stem cell-derived islet spheroid system

Remarkable advances in protocol development have been achieved to manufacture insulin-secreting islets from human pluripotent stem cells (hPSCs). Distinct from current approaches, we devised a tunable strategy to generate islet spheroids enriched for major islet cell types by incorporating PDX1+ cell budding morphogenesis into staged differentiation. In this process that appears to mimic normal islet morphogenesis, the differentiating islet spheroids organize with endocrine cells that are intermingled or arranged in a core-mantle architecture, accompanied with functional heterogeneity. Through in vitro modelling of human pancreas development, we illustrate the importance of PDX1 and the requirement for EphB3/4 signaling in eliciting cell budding morphogenesis. Using this new approach, we model Mitchell-Riley syndrome with RFX6 knockout hPSCs illustrating unexpected morphogenesis defects in the differentiation towards islet cells. The tunable differentiation system and stem cell-derived islet models described in this work may facilitate addressing fundamental questions in islet biology and probing human pancreas diseases.

Morphogenesis, megagametogenesis, and microgametogenesis in Actinidia arguta flower buds

In dioecious plants, understanding sexual differentiation is important for improving cultivation techniques. Flower bud morphogenesis and gametophyte formation underlie the mechanism of sexual differentiation. Actinidia arguta (hardy kiwi) is a unisexual plant, and there have been few studies on its flower bud differentiation or gametophyte formation. We studied flower bud morphogenesis and gametophyte formation in A. arguta using paraffin sections and found that the morphogenesis of male and female flower buds was divided into six stages: the undifferentiated stage, inflorescence initials differentiation stage, calyx primordium differentiation stage, petal primordium differentiation stage, stamen primordium differentiation stage, and pistil primordium differentiation stage. Morphogenesis in the male inflorescence can reach quaternary flower primordia, and morphogenesis in the female inflorescence can reach the tertiary flower primordia, however, no Stage 4 lateral flowers in the male inflorescence or Stage 3 lateral flowers in the female inflorescence were found in natural situation. The embryo sac in female plants was a monocellular Polygonum type, and the embryo sac development in male plants was incomplete; abortion occurred before the archesporial cells developed. The male gametophyte differentiation process in the male plant was normal, with pollen grains similar in shape to a rugby ball and arranged neatly in the anther. The pollen grain differentiation in female plants was abnormal; abortion occurred at the uninucleate microspore stage, and mature pollen grains were irregularly spherical.

Profiles of Wnt pathway gene expression during tooth morphogenesis.

Mouse and human genetic studies indicate key roles of the Wnt10a ligand in odontogenesis. Previous studies have identified effectors and regulators of the Wnt signaling pathway actively expressed during key stages of tooth morphogenesis. However, limitations in multiplexing and spatial resolution hindered a more comprehensive analysis of these signaling molecules. Here, profiling of transcriptomes using fluorescent multiplex in situ hybridization and single-cell RNA-sequencing (scRNA-seq) provide robust insight into the synchronized expression patterns of Wnt10a, Dkk1, and Sost simultaneously during tooth development. First, we identified Wnt10a transcripts restricted to the epithelium at the stage of tooth bud morphogenesis, contrasting that of Sost and Dkk1 localization to the dental mesenchyme. By embryonic day 15.5 (E15.5), a marked shift of Wnt10a expression from dental epithelium to mesenchyme was noted, while Sost and Dkk1 expression remained enriched in the mesenchyme. By postnatal day 0 (P0), co-localization patterns of Wnt10a, Dkk1, and Sost were observed in both terminally differentiating and secreting odontoblasts of molars and incisors. Interestingly, Wnt10a exhibited robust expression in fully differentiated ameloblasts at the developing cusp tip of both molars and incisors, an observation not previously noted in prior studies. At P7 and 14, after the mineralization of dentin and enamel, Wnt10a expression was limited to odontoblasts. Meanwhile, Wnt modulators showed reduced or absent signals in molars. In contrast, strong signals persisted in ameloblasts (for Wnt10a) and odontoblasts (for Wnt10a, Sost, and Dkk1) towards the proximal end of incisors, near the cervical loop. Our scRNA-seq analysis used CellChat to further contextualize Wnt pathway-mediated communication between cells by examining ligand-receptor interactions among different clusters. The co-localization pattern of Wnt10a, Dkk1, and Sost in both terminally differentiating and secreting odontoblasts of molars and incisors potentially signifies the crucial ligand-modulator interaction along the gradient of cytodifferentiation starting from each cusp tip towards the apical region. These data provide cell type-specific insight into the role of Wnt ligands and mediators during epithelial-mesenchymal interactions in odontogenesis.

Novel Aspects in Pattern Formation Arise from Coupling Turing Reaction–Diffusion and Chemotaxis

Recent experimental studies on primary hair follicle formation and feather bud morphogenesis indicate a coupling between Turing-type diffusion driven instability and chemotactic patterning. Inspired by these findings we develop and analyse a mathematical model that couples chemotaxis to a reaction–diffusion system exhibiting diffusion–driven (Turing) instability. While both systems, reaction–diffusion systems and chemotaxis, can independently generate spatial patterns, we were interested in how the coupling impacts the stability of the system, parameter region for patterning, pattern geometry, as well as the dynamics of pattern formation. We conduct a classical linear stability analysis for different model structures, and confirm our results by numerical analysis of the system. Our results show that the coupling generally increases the robustness of the patterning process by enlarging the pattern region in the parameter space. Concerning time scale and pattern regularity, we find that an increase in the chemosensitivity can speed up the patterning process for parameters inside and outside of the Turing space, but generally reduces spatial regularity of the pattern. Interestingly, our analysis indicates that pattern formation can also occur when neither the Turing nor the chemotaxis system can independently generate pattern. On the other hand, for some parameter settings, the coupling of the two processes can extinguish the pattern formation, rather than reinforce it. These theoretical findings can be used to corroborate the biological findings on morphogenesis and guide future experimental studies. From a mathematical point of view, this work sheds a light on coupling classical pattern formation systems from the parameter space perspective.

GPIbα–filamin A interaction regulates megakaryocyte localization and budding during platelet biogenesis

AbstractGlycoprotein Ibα (GPIbα) is expressed on the surface of platelets and megakaryocytes (MKs) and anchored to the membrane skeleton by filamin A (flnA). Although GPIb and flnA have fundamental roles in platelet biogenesis, the nature of this interaction in megakaryocyte biology remains ill-defined. We generated a mouse model expressing either human wild-type (WT) GPIbα (hGPIbαWT) or a flnA-binding mutant (hGPIbαFW) and lacking endogenous mouse GPIbα. Mice expressing the mutant GPIbα transgene exhibited macrothrombocytopenia with preserved GPIb surface expression. Platelet clearance was normal and differentiation of MKs to proplatelets was unimpaired in hGPIbαFW mice. The most striking abnormalities in hGPIbαFW MKs were the defective formation of the demarcation membrane system (DMS) and the redistribution of flnA from the cytoplasm to the peripheral margin of MKs. These abnormalities led to disorganized internal MK membranes and the generation of enlarged megakaryocyte membrane buds. The defective flnA-GPIbα interaction also resulted in misdirected release of buds away from the vasculature into bone marrow interstitium. Restoring the linkage between flnA and GPIbα corrected the flnA redistribution within MKs and DMS ultrastructural defects as well as restored normal bud size and release into sinusoids. These studies define a new mechanism of macrothrombocytopenia resulting from dysregulated MK budding. The link between flnA and GPIbα is not essential for the MK budding process, however, it plays a major role in regulating the structure of the DMS, bud morphogenesis, and the localized release of buds into the circulation.

Recombinant expression and preliminary characterization of Peptidyl-prolyl cis/trans-isomerase Rrd1 from Saccharomyces cerevisiae.

Sacchromycescerevisiae Peptidyl-prolylcis/trans-isomerase Rrd1 has been linked to DNA repair, bud morphogenesis, advancement of the G1 phase, DNA replication stress, microtubule dynamics and is also necessary for the quick decrease in Sgs1p levels in response to rapamycin. In present study, Rrd1 gene was amplified by standard PCR and subsequently cloned downstream to bacteriophage T7 inducible promoter and lac operator of expression vector pET21d(+). Additionally, immobilized metal affinity chromatography (IMAC) was used to purify the protein upto its homogeneity, and its homogeneous purity was further confirmed through western blotting. Size exclusion chromatography implies that Rrd1 is existing as monomer in its natural state. Foldwise Rrd1 protein belongs to PTPA-like protein superfamily. Rrd1 showed characteristic negative minima at 222 and 208 nm represent protein typically acquired α helix in the far-UV CD spectra. Fluorescence spectra showed properly folded tertiary structures of Rrd1 at physiological conditions. Rrd1protein can be identified from different species using a fingerprint created by PIPSA analysis. The protein's abundance could aid in its crystallization, biophysical characterization and identification of other-interacting partners of Rrd1 protein.

ASH2L Controls Ureteric Bud Morphogenesis through the Regulation of RET/GFRA1 Signaling Activity in a Mouse Model.

Causes of congenital anomalies of the kidney and urinary tract (CAKUT) remain unclear. The authors investigated whether and how inactivation of Ash2l -which encodes a subunit of the COMPASS methyltransferase responsible for genome-wide histone H3 lysine K4 (H3K4) methylation-might contribute to CAKUT. In a mouse model, inactivation of Ash2l in the ureteric bud (UB) lineage led to CAKUT-like phenotypes. Removal of ASH2L led to deficient H3K4 trimethylation, which slowed cell proliferation at the UB tip, delaying budding and impairing branching morphogenesis. The absence of ASH2L also downregulated the expression of Ret , Gfra1 , and Wnt11 genes involved in RET/GFRA1 signaling. These findings identify ASH2L-mediated H3K4 methylation as an upstream epigenetic regulator of signaling crucial for UB morphogenesis and indicate that deficiency or dysregulation of these processes may lead to CAKUT. Ureteric bud (UB) induction and branching morphogenesis are fundamental to the establishment of the renal architecture and are key determinants of nephron number. Defective UB morphogenesis could give rise to a spectrum of malformations associated with congenital anomalies of the kidney and urinary tract (CAKUT). Signaling involving glial cell line-derived neurotrophic factor and its receptor rearranged during transfection (RET) and coreceptor GFRA1 seems to be particularly important in UB development. Recent epigenome profiling studies have uncovered dynamic changes of histone H3 lysine K4 (H3K4) methylation during metanephros development, and dysregulated H3K4 methylation has been associated with a syndromic human CAKUT. To investigate whether and how inactivation of Ash2l , which encodes a subunit of the COMPASS methyltransferase responsible for genome-wide H3K4 methylation, might contribute to CAKUT, we inactivated Ash2l specifically from the UB lineage in C57BL/6 mice and examined the effects on genome-wide H3K4 methylation and metanephros development. Genes and epigenome changes potentially involved in these effects were screened using RNA-seq combined with Cleavage Under Targets and Tagmentation sequencing. UB-specific inactivation of Ash2l caused CAKUT-like phenotypes mainly involving renal dysplasia at birth, which were associated with deficient H3K4 trimethylation. Ash2l inactivation slowed proliferation of cells at the UB tip, delaying budding and impairing UB branching morphogenesis. These effects were associated with downregulation of Ret , Gfra1 , and Wnt11 , which participate in RET/GFRA1 signaling. These experiments identify ASH2L-dependent H3K4 methylation in the UB lineage as an upstream epigenetic regulator of RET/GFRA1 signaling in UB morphogenesis, which, if deficient, may lead to CAKUT.

Morfogenesis Kalus Sorgum Pada Berbagai Media Secara In Vitro

Sorghum has great potential to be developed as a food source in Indonesia because it has many benefits. Sorghum has various potentials and uses, such as as a source of functional food, industrial raw materials and also animal feed. All parts of the sorghum plant can be utilized. Genetic transformation will be successful and beneficial if a plant regeneration system has been obtained in vitro culture. In its implementation, the selection of explants is an important first step to support the success of in vitro culture. Generally, the explants used for tissue culture are shoot tips, lateral shoots, and epicotyls. This study aims todetermine the morphogenesis of sorghum in vitro, from tissue culture. The analysis method in this study used 3 treatments, namely Murashige & Skoog (MS), Vacint & Went (VW) and Nagata & Takebe (NT) media with repeated 5 times. The method of analysis with data on the percentage of living callus and observing the morphogenesis of growing shoots and calluses. The result of this study is that the treatment of Murashige & Skoog (MS) media affects the morphogenesis of buds in the form of the number of perexplant shoots, the number of leaves, and the length of the shoots with the best treatment. The number of shoots per growing explant by 85%. The treatment of Vacint & Went (VW) and Nagata & Takebe (NT) media did not have enough effect on callus induction in the form of growth and development of callus planted in-vitro. So that the morphagenics of sorghum plants are good in the growth of shoots on Murashige & Skoog (MS) media.

Binding Pattern Reconstructions of FGF-FGFR Budding-Inducing Signaling in Reef-Building Corals.

Reef-building corals play an important role in marine ecosystems. However, owing to climate change, ocean acidification, and predation by invasive crown-of-thorns starfish, these corals are declining. As marine animals comprise polyps, reproduction by asexual budding is pivotal in scleractinian coral growth. The fibroblast growth factor (FGF) signaling pathway is essential in coral budding morphogenesis. Here, we sequenced the full-length transcriptomes of four common and frequently dominant reef-building corals and screened out the budding-related FGF and FGFR genes. Thereafter, three-dimensional (3D) models of FGF and FGFR proteins as well as FGF-FGFR binding models were reconstructed. Based on our findings, the FGF8-FGFR3 binding models in Pocillopora damicornis, Montipora capricornis, and Acropora muricata are typical receptor tyrosine kinase-signaling pathways that are similar to the Kringelchen (FGFR) in hydra. However, in P. verrucosa, FGF8 is not the FGFR3 ligand, which is found in other hydrozoan animals, and its FGFR3 must be activated by other tyrosine kinase-type ligands. Overall, this study provides background on the potentially budding propagation signaling pathway activated by the applications of biological agents in reef-building coral culture that could aid in the future restoration of coral reefs.

Jack of all trades, master of each: the diversity of fibroblast growth factor signalling in eye development.

A central question in development biology is how a limited set of signalling pathways can instruct unlimited diversity of multicellular organisms. In this review, we use three ocular tissues as models of increasing complexity to present the astounding versatility of fibroblast growth factor (FGF) signalling. In the lacrimal gland, we highlight the specificity of FGF signalling in a one-dimensional model of budding morphogenesis. In the lens, we showcase the dynamics of FGF signalling in altering functional outcomes in a two-dimensional space. In the retina, we present the prolific utilization of FGF signalling from three-dimensional development to homeostasis. These examples not only shed light on the cellular basis for the perfection and complexity of ocular development, but also serve as paradigms for the diversity of FGF signalling.

Spatiotemporal imaging and analysis of mouse and human liver bud morphogenesis.

The process of liver organogenesis has served as a paradigm for organ formation. However, there remains a lack of understanding regarding early mouse and human liver bud morphogenesis and early liver volumetric growth. Elucidating dynamic changes in liver volumes is critical for understanding organ development, implementing toxicological studies, and for modeling hPSC-derived liver organoid growth. New visualization, analysis, and experimental techniques are desperately needed. Here, we combine observational data with digital resources, new 3D imaging approaches, retrospective analysis of liver volume data, mathematical modeling, and experiments with hPSC-derived liver organoids. Mouse and human liver organogenesis, characterized by exponential growth, demonstrate distinct spatial features and growth curves over time, which we mathematically modeled using Gompertz models. Visualization of liver-epithelial and septum transversum mesenchyme (STM) interactions suggests extended interactions, which together with new spatial features may be responsible for extensive exponential growth. These STM interactions are modeled with a novel in vitro human pluripotent stem cell (hPSC)-derived hepatic organoid system that exhibits cell migration. Our methods enhance our understanding of liver organogenesis, with new 3D visualization, analysis, mathematical modeling, and in vitro models with hPSCs. Our approach highlights mouse and human differences and provides potential hypothesis for further investigation in vitro and in vivo.

Conserved and species-specific chromatin remodeling and regulatory dynamics during mouse and chicken limb bud development

Chromatin remodeling and genomic alterations impact spatio-temporal regulation of gene expression, which is central to embryonic development. The analysis of mouse and chicken limb development provides important insights into the morphoregulatory mechanisms, however little is known about the regulatory differences underlying their morphological divergence. Here, we identify the underlying shared and species-specific epigenomic and genomic variations. In mouse forelimb buds, we observe striking synchrony between the temporal dynamics of chromatin accessibility and gene expression, while their divergence in chicken wing buds uncovers species-specific regulatory heterochrony. In silico mapping of transcription factor binding sites and computational footprinting establishes the developmental time-restricted transcription factor-DNA interactions. Finally, the construction of target gene networks for HAND2 and GLI3 transcriptional regulators reveals both conserved and species-specific interactions. Our analysis reveals the impact of genome evolution on the regulatory interactions orchestrating vertebrate limb bud morphogenesis and provides a molecular framework for comparative Evo-Devo studies.

Docking to a Basic Helix Promotes Specific Phosphorylation by G1-Cdk1.

Cyclins are the activators of cyclin-dependent kinase (CDK) complex, but they also act as docking scaffolds for different short linear motifs (SLiMs) in CDK substrates and inhibitors. According to the unified model of CDK function, the cell cycle is coordinated by CDK both via general CDK activity thresholds and cyclin-specific substrate docking. Recently, it was found that the G1-cyclins of S. cerevisiae have a specific function in promoting polarization and growth of the buds, making the G1 cyclins essential for cell survival. Thus, while a uniform CDK specificity of a single cyclin can be sufficient to drive the cell cycle in some cells, such as in fission yeast, cyclin specificity can be essential in other organisms. However, the known G1-CDK specific LP docking motif, was not responsible for this essential function, indicating that G1-CDKs use yet other unknown docking mechanisms. Here we report a discovery of a G1 cyclin-specific (Cln1,2) lysine-arginine-rich helical docking motif (the K/R motif) in G1-CDK targets involved in the mating pathway (Ste7), transcription (Xbp1), bud morphogenesis (Bud2) and spindle pole body (Spc29, Spc42, Spc110, Sli15) function of S. cerevisiae. We also show that the docking efficiency of K/R motif can be regulated by basophilic kinases such as protein kinase A. Our results further widen the list of cyclin specificity mechanisms and may explain the recently demonstrated unique essential function of G1 cyclins in budding yeast.

External surface anatomy of the postfolding human embryo: Computer-aided, three-dimensional reconstruction of printable digital specimens.

Opportunities for clinicians, researchers, and medical students to become acquainted with the three‐dimensional (3D) anatomy of the human embryo have historically been limited. This work was aimed at creating a collection of digital, printable 3D surface models demonstrating major morphogenetic changes in the embryo's external anatomy, including typical features used for external staging. Twelve models were digitally reconstructed based on optical projection tomography, high‐resolution episcopic microscopy and magnetic resonance imaging datasets of formalin‐fixed specimens of embryos of developmental stages 12 through 23, that is, stages following longitudinal and transverse embryo folding. The reconstructed replica reproduced the external anatomy of the actual specimens in great detail, and the progress of development over stages was recognizable in a variety of external anatomical features and bodily structures, including the general layout and curvature of the body, the pharyngeal arches and cervical sinus, the physiological gut herniation, and external genitalia. In addition, surface anatomy features commonly used for embryo staging, such as distinct steps in the morphogenesis of facial primordia and limb buds, were also apparent. These digital replica, which are all provided for 3D visualization and printing, can serve as a novel resource for teaching and learning embryology and may contribute to a better appreciation of the human embryonic development.

Budding epithelial morphogenesis driven by cell-matrix versus cell-cell adhesion

Many embryonic organs undergo epithelial morphogenesis to form tree-like hierarchical structures. However, it remains unclear what drives the budding and branching of stratified epithelia, such as in the embryonic salivary gland and pancreas. Here, we performed live-organ imaging of mouse embryonic salivary glands at single-cell resolution to reveal that budding morphogenesis is driven by expansion and folding of a distinct epithelial surface cell sheet characterized by strong cell-matrix adhesions and weak cell-cell adhesions. Profiling of single-cell transcriptomes of this epithelium revealed spatial patterns of transcription underlying these cell adhesion differences. We then synthetically reconstituted budding morphogenesis by experimentally suppressing E-cadherin expression and inducing basement membrane formation in 3D spheroid cultures of engineered cells, which required β1-integrin-mediated cell-matrix adhesion for successful budding. Thus, stratified epithelial budding, the key first step of branching morphogenesis, is driven by an overall combination of strong cell-matrix adhesion and weak cell-cell adhesion by peripheral epithelial cells.

Confirmation of “pre-plasmolysis mediated ex-osmosis hypothesis” to obtain shoot bud morphogenesis in Catharanthus roseus

The antineoplastic herb, Catharanthus roseus is a classified high-value low-volume medicinal herb which is in global attention of scientific research for modulation of its monoterpenoid indole alkaloids (MIA) pathway through genetic engineering. These secondary metabolites are generally stored in specific types of structures/compartments due to their cytotoxic nature and designated roles in plant defense response. However, their presence can hinder the genetic engineering process used to develop transgenic plants through de novo morphogenesis and regeneration of plants from cultured cells/tissues and hence, it always remained a critical impediment in transgenic research in C. roseus. The pre-plasmolysis treatment of leaf explants can help to tackle the recalcitrant nature of leaf explant and can support the direct regeneration response by ex-osmosis that minimizes the concentration of alkaloids. Therefore, this study was performed to chase the effect of osmotic conditions on recalcitrant leaves of C. roseus engaged in vitro plant regeneration and hypothesis of alkaloids ex-osmosis is confirmed by HPLC analysis.

The morphogenesis of vegetative buds of Picea species (Pinaceae), introduced in the taiga zone (Karelia)

The observations were carried out in the Botanical garden of the Petrozavodsk state University, located in the taiga zone. Objects of research served 1 native and 5 introduced species: Picea abies (L.) Karst., P. obovata Ledeb., P. mariana Britt., P. glauca (Mill.) Вritt., P. pungens Engelm., P. omorica (Pane) Purk. The study of morphogenesis in vegetative buds was carried out axial shoots from the middle part of the crown since the beginning of the bud swelling until the cessation of laying primordial needles (May to September). The growing shoots are cut off after 2-3 days and were fixed in a mixture of alcohol and glycerin. For the start date of a stage, took the time when it was noted in not less than 30% of the buds. It is established that intrarenal development of vegetative organs from the native species P. abies was studied and introduced species of the genus Picea characterized by similar phases: rest, laying cover scales and laying primordial needles. Morphogenesis of vegetative buds of P. abies on the timing ahead of the development of the bud in the introduced species, which indicates a much greater insistence of the latter to temperature. The duration of the morphogenesis of the buds in all studied types varies slightly (days 131-137). However, the morphogenesis of vegetative buds of native species for 1-4 weeks ahead in terms of development of the buds in introduced species with a similarity of morphogenesis of the bud (P. abies and P. glauca), the value of the annual increment of the shoots is almost the same.

Epithelial Morphogenesis Driven by Cell-Matrix vs. Cell-Cell Adhesion

Many embryonic organs undergo epithelial morphogenesis to form tree-like hierarchical structures. However, it remains unclear what drives the budding and branching of stratified epithelia, such as in embryonic salivary gland and pancreas. Here, we performed live-organ imaging of mouse embryonic salivary glands at single-cell resolution to reveal that budding morphogenesis is driven by expansion and folding of a distinct epithelial surface cell sheet characterized by strong cell-matrix adhesions and weak cell-cell adhesions. Profiling of single-cell transcriptomes of this epithelium revealed spatial patterns of transcription underlying these cell adhesion differences. We then synthetically reconstituted budding morphogenesis by experimentally suppressing E-cadherin expression and inducing basement membrane formation in 3D spheroid cultures of engineered cells, which required β1 integrin-mediated cell-matrix adhesion for successful budding. Thus, stratified epithelial budding, the key first step of branching morphogenesis, is driven by an overall combination of strong cell-matrix adhesion and weak cell-cell adhesion by peripheral epithelial cells.