ABSTRACT
Leaves and flowers begin life as outgrowths from the edges of shoot apical meristems. Stem cell divisions in the meristem center replenish cells that are incorporated into organ primordia at the meristem periphery and leave the meristem. Organ boundaries, regions of limited growth that separate forming organs from the meristem, serve to isolate these two domains and are critical for coordination of organogenesis and meristem maintenance. Boundary formation and maintenance are poorly understood processes, despite the identification of a number of boundary-specific transcription factors. Here we provide genetic and biochemical evidence that the Arabidopsis thaliana transcription factor lateral organ boundaries (LOB) negatively regulates accumulation of the plant steroid hormone brassinosteroid (BR) in organ boundaries. We found that ectopic expression of LOB results in reduced BR responses. We identified BAS1, which encodes a BR-inactivating enzyme, as a direct target of LOB transcriptional activation. Loss-of-function lob mutants exhibit organ fusions, and this phenotype is suppressed by expression of BAS1 under the LOB promoter, indicating that BR hyperaccumulation contributes to the lob mutant phenotype. In addition, LOB expression is BR regulated; therefore, LOB and BR form a feedback loop to modulate local BR accumulation in organ boundaries to limit growth in the boundary domain.
Subject(s)
Arabidopsis Proteins/physiology , Arabidopsis/genetics , Brassinosteroids/metabolism , Alleles , Arabidopsis/metabolism , Arabidopsis Proteins/genetics , Arabidopsis Proteins/metabolism , Gene Expression Regulation, Plant , Genes, Plant , Models, Genetic , Mutation , Phenotype , Plants/metabolism , Promoter Regions, Genetic , Time Factors , Transcription, GeneticABSTRACT
Coil stretching is a recognized complication during cerebral aneurysm embolization.1, 3- 5 For over a decade, the microsnare has proven effective in retrieving migrated coils.1- 5 Fiorella et al. unveiled the "Monorail Snare Technique" in 2005, offering a specialized approach to stretched coil recovery.1 However, to gain a complete understanding of this technique, more than just textual descriptions are necessary; a thorough, practical demonstration is essential. In our technical video (video 1), we illustrated an episode of coil stretching during aneurysm embolization, where the "Monorail Snare Technique" was successfully employed to retrieve a stretched coil. Our video emphasizes the meticulous preparation and modification of the microsnare, showcasing enhanced steps to mitigate the potential blood backflow triggered by the exclusive use of one-arm hemostasis valve during the "Monorail Snare Technique."1, 5 This pivotal adjustment substantially lowers the threat of thromboembolic events. We highlighted essential precautions to ensure the procedure's safety and efficacy.4, 5.
ABSTRACT
Cardiovascular diseases (CVDs) stand as a predominant global health concern, introducing vast socioeconomic challenges. In addressing this pressing dilemma, enhanced diagnostic modalities have become paramount, positioning electrochemical biosensing as an instrumental innovation. This comprehensive review navigates the multifaceted terrain of CVDs, elucidating their defining characteristics, clinical manifestations, therapeutic avenues, and intrinsic risk factors. Notable emphasis is placed on pivotal diagnostic tools, spotlighting cardiac biomarkers distinguished by their unmatched clinical precision in terms of relevance, sensitivity, and specificity. Highlighting the broader repercussions of CVDs, there emerges an accentuated need for refined diagnostic strategies. Such an exploration segues into a profound analysis of electrochemical biosensing, encapsulating its foundational principles, diverse classifications, and integral components, notably recognition molecules and transducers. Contemporary advancements in biosensing technologies are brought to the fore, emphasizing pioneering electrode architectures, cutting-edge signal amplification processes, and the synergistic integration of biosensors with microfluidic platforms. At the core of this discourse is the demonstrated proficiency of biosensors in detecting cardiovascular anomalies, underpinned by empirical case studies, systematic evaluations, and clinical insights. As the narrative unfolds, it addresses an array of inherent challenges, spanning intricate technicalities, real-world applicability constraints, and regulatory considerations, finally, by casting an anticipatory gaze upon the future of electrochemical biosensing, heralding a new era of diagnostic tools primed to revolutionize cardiovascular healthcare.
Subject(s)
Biomarkers , Biosensing Techniques , Cardiovascular Diseases , Electrochemical Techniques , Humans , Cardiovascular Diseases/diagnosis , Biomarkers/analysis , Biomarkers/bloodABSTRACT
Mercury's neurotoxic effects have prompted the development of advanced control and remediation methods to meet stringent measures for industries with high-mercury feedstocks. Industries with significant Hg emissions, including artisanal and small-scale gold mining (ASGM)-789.2 Mg year-1, coal combustion-564.1 Mg year-1, waste combustion-316.1 Mg year-1, cement production-224.5 Mg year-1, and non-ferrous metals smelting-204.1 Mg year-1, use oxidants and adsorbents capture Hg from waste streams. Oxidizing agents such as O3, Cl2, HCl, CaBr2, CaCl2, and NH4Cl oxidize Hg0 to Hg2+ for easier adsorption. To functionalize adsorbents, carbonaceous ones use S, SO2, and Na2S, metal-based adsorbents use dimercaprol, and polymer-based adsorbents are grafted with acrylonitrile and hydroxylamine hydrochloride. Adsorption capacities span 0.2-85.6 mg g-1 for carbonaceous, 0.5-14.8 mg g-1 for metal-based, and 168.1-1216 mg g-1 for polymer-based adsorbents. Assessing Hg contamination in soils and sediments uses bioindicators and stable isotopes. Remediation approaches include heat treatment, chemical stabilization and immobilization, and phytoremediation techniques when contamination exceeds thresholds. Achieving a substantially Hg-free ecosystem remains a formidable challenge, chiefly due to the ASGM industry, policy gaps, and Hg persistence. Nevertheless, improvements in adsorbent technologies hold potential.
ABSTRACT
In distal vascular lesions, such as the distal anterior inferior cerebellar artery or posterior inferior cerebellar artery (PICA) dissecting aneurysm, and dural arteriovenous fistula (dAVF) and arteriovenous malformation (AVM), super-selective catheterization and embolization using liquid agents, such as NBCA or Onyx liquid embolic system, is the preferred treatment.1 2 We used a flow-directed 1.5 Fr Marathon microcatheter (Medtronic, Minneapolis, MN, USA) for embolization because commonly used detachable coil-compatible microcatheters can be too short or rigid for superselection.3-6 We designed an in vitro coil compatibility test for the Marathon microcatheter and developed a 'free-running' technique (video 1). Using this technique, we trapped the distal PICA dissecting aneurysm and embolized the fistula points of dAVF precisely and safely without affecting adjacent normal structures, which can occur when applying liquid embolizing agents.1-3 After reviewing the case, we determined that this technique can also potentially be applied for implementing the pressure cooker technique7 and combining the management of AVM.4neurintsurg;jnis-2023-020893v1/V1F1V1Video 1Free-running technique via 1.5 Fr Marathon microcatheter.
ABSTRACT
The LATERAL ORGAN BOUNDARIES DOMAIN (LBD) gene family encodes plant-specific transcription factors. In this report, the LBD gene DOWN IN DARK AND AUXIN1 (DDA1), which is closely related to LATERAL ORGAN BOUNDARIES (LOB) and ASYMMETRIC LEAVES2 (AS2), was characterized. DDA1 is expressed primarily in vascular tissues and its transcript levels were reduced by exposure to exogenous indole-3-acetic acid (IAA or auxin) and in response to dark exposure. Analysis of a T-DNA insertion line, dda1-1, in which the insertion resulted in misregulation of DDA1 transcripts in the presence of IAA and in the dark revealed possible functions in auxin response and photomorphogenesis. dda1-1 plants exhibited reduced sensitivity to auxin, produced fewer lateral roots, and displayed aberrant hypocotyl elongation in the dark. Phenotypes resulting from fusion of a transcriptional repression domain to DDA1 suggest that DDA1 may act as both a transcriptional activator and a transcriptional repressor depending on the context. These results indicate that DDA1 may function in both the auxin signalling and photomorphogenesis pathways.
Subject(s)
Arabidopsis Proteins/metabolism , Arabidopsis/metabolism , Arabidopsis/radiation effects , Gene Expression Regulation, Plant , Indoleacetic Acids/metabolism , Signal Transduction , Transcription Factors/metabolism , Arabidopsis/chemistry , Arabidopsis/genetics , Arabidopsis Proteins/chemistry , Arabidopsis Proteins/genetics , Gene Expression Regulation, Plant/radiation effects , Light , Protein Structure, Tertiary , Signal Transduction/radiation effects , Transcription Factors/chemistry , Transcription Factors/geneticsABSTRACT
Lateral organ polarity in Arabidopsis is regulated by antagonistic interactions between genes that promote either adaxial or abaxial identity, but the molecular basis of this interaction is largely unknown. We show that the adaxial regulator ASYMMETRIC LEAVES2 (AS2) is a direct target of the abaxial regulator KANADI1 (KAN1), and that KAN1 represses the transcription of AS2 in abaxial cells. Mutation of a single nucleotide in a KAN1 binding site in the AS2 promoter causes AS2 to be ectopically expressed in abaxial cells, resulting in a dominant, adaxialized phenotype. We also show that the abaxial expression of KAN1 is mediated directly or indirectly by AS2. These results demonstrate that KAN1 acts as a transcriptional repressor and that mutually repressive interactions between KAN1 and AS2 contribute to the establishment of adaxial-abaxial polarity in plants.
Subject(s)
Arabidopsis Proteins/metabolism , Arabidopsis/growth & development , Arabidopsis/metabolism , Gene Expression Regulation, Plant , Transcription Factors/metabolism , Transcription, Genetic/genetics , Arabidopsis/genetics , Arabidopsis Proteins/genetics , Base Sequence , Binding Sites , Mutation/genetics , Phenotype , Plants, Genetically Modified , Transcription Factors/geneticsABSTRACT
We present a transvenous embolization technique for a direct carotid-cavernous fistula through the pterygoid plexus to the cavernous sinus which only 2 cases have been previously reported in the English literature. This method is appropriate when transarterial techniques or other attempts at transvenous access have failed due to vessel tortuosity, hypoplasia, stenosis, or occlusion. A middle-aged female patient presented with progressive left exophthalmos with conjunctiva chemosis and bruit after sustaining a falling injury. Digital subtraction angiography revealed Barrow type A carotid-cavernous fistula. The drainage route passed through a distal thrombosed superior ophthalmic vein that ended deep in the orbit. No other patent venous sinuses connected to the cavernous sinus, except for a small tract of pterygoid plexus. After failure of transarterial approach and other methods of transvenous access, we attempted to superselectly access to the cavernous sinus by applying transpterygoid technique with embolization using detachable coils. The transpterygoid venous approach to accessing the cavernous sinus represents an alternative approach when other techniques fail.
ABSTRACT
PURPOSE: Extracorporeal shock wave (ESW) has been introduced to enhance spinal fusion. This study was conducted to assess the effect of ESW on bone morphogenetic protein-2 (BMP-2) expression in a spinal fusion experiment. METHODS: Twelve rabbits underwent fusion at bilateral L5-6 intertransverse spaces. They were evenly divided into two groups. In the study group, bilateral L5 and L6 transverse processes were treated with 1,000 impulses of ESW at 14 kV at 12 weeks. In the control group, the rabbits did not receive ESW treatment. All rabbits were sacrificed at 16 weeks, and their lumbar spines were harvested for radiographic and molecular biological study. RESULTS: In the study group (n = 6), the radiographs showed good fusion in all six rabbits, while in the control group (n = 6), good fusion was found only in three rabbits (50%). Although more rabbits in the study group had a good fusion result, the inter-group difference was not statistically significant (P = 0.182). In the molecular biological examination, the mean value of the normalized expression of BMP-2 mRNA in the fusion masses of the study group was 90 ± 8.4 while that of the control group was 77.33 ± 6.74. Statistical analysis showed the study group had a significantly higher BMP-2 mRNA expression in the fusion masses than the control group (P = 0.018). CONCLUSIONS: The current study showed that ESW treatment enhances BMP-2 mRNA expression in spinal fusion masses.
Subject(s)
Bone Morphogenetic Protein 2/genetics , Lithotripsy/methods , Lumbar Vertebrae/metabolism , Lumbar Vertebrae/surgery , RNA, Messenger/metabolism , Spinal Fusion/methods , Acoustic Stimulation/methods , Animals , Bone Regeneration/physiology , Disease Models, Animal , Lumbar Vertebrae/diagnostic imaging , Male , Osteogenesis/physiology , Rabbits , Radiography , Treatment Outcome , Up-Regulation/physiology , Wound Healing/physiologyABSTRACT
BACKGROUND: Extracorporeal shock wave treatment has been used to treat many orthopedic disorders. However, the effect of extracorporeal shock waves on spinal fusion has not been reported. METHODS: Fifteen rabbits were used in this study. Spinal fusion was performed with decortication of bilateral L5 and L6 transverse processes, and placement of the bone chips onto the ipsilateral L5-L6 intertransverse space. The right L5 and L6 transverse processes in all animals were treated with 1000 impulses of ESWT at 14 kV (equivalent to 0.18 mJ/mm(2)) at 3 and 6 weeks after surgery. The left transverse processes did not receive ESWT, and were served as controls. Radiographic examinations of the spines were performed at 3, 6, and 12 weeks. Computed tomography was performed at 12 weeks. The rabbits were killed at 12 weeks, and the spinal segments were harvested for histomorphological examination. RESULTS: Radiographs of the tested rabbits taken at different post-ESWT stages demonstrated repairing effect of ESWT on the fusion gap of the treated (right) sides. Statistical analysis of the image studies indicated that 11 (73%) of 15 rabbits showed superior fusion mass on the ESWT (right) side than that of control (left) side (P < .001). The remaining 4 (27%) rabbits showed no discernable fusion difference between the ESWT side and the control side. Histomorphological examination showed good new bone formation in 9 fusion masses. All of these cases were noted on the ESWT (right) sides. Statistical analysis showed that ESWT sides had better new bone formation than the control sides (P = .001). CONCLUSIONS: Results of this study demonstrated that ESWT is effective in promoting spinal fusion in rabbits.
Subject(s)
High-Energy Shock Waves/therapeutic use , Lumbar Vertebrae/diagnostic imaging , Lumbar Vertebrae/surgery , Osteogenesis/radiation effects , Spinal Fusion/methods , Animals , Bone Transplantation , Lumbosacral Region , Male , Models, Animal , Osteogenesis/physiology , Rabbits , Tomography, X-Ray Computed , Treatment Outcome , UltrasonographyABSTRACT
RATIONALE: Splenic artery embolization (SAE) is a common procedure in trauma patients with blunt splenic injuries. We report a case of acute ischemic stroke following orthopedic surgery in a patient with post-SAE reactive thrombocytosis. PATIENT CONCERNS: A 37-year-old woman with idiopathic thrombocytopenic purpura (ITP) suffered from multiple trauma scheduled for open reduction and internal fixation for right tibial and left radius fracture five days after SAE. The patient did not have any thromboembolic complications, although the platelet counts increased from 43â×â10/L to 568â×â10/L within two days after SAE. Surgery was completed under general anesthesia with tracheal intubation without complications. The patient complained of visual loss followed by limb weakness on the fourth and eighth hour postoperatively. DIAGNOSES: Magnetic resonance imaging (MRI) of head demonstrated ischemic change over bilateral basal ganglia, and occipital areas, suggesting the diagnosis of cortical blindness. INTERVENTIONS: To suppress platelet count and avoid platelet hyper-aggregation, anti-platelet drug (i.e., oral aspirin 100âmg daily), hydration, and hydroxyurea (i.e., 20âmg/kg daily) were used for the treatment of reactive thrombocytosis. OUTCOMES: Although right-sided hemiparesis persisted, the patient reported mild visual recovery. She was discharged four months after SAE with active rehabilitation. LESSONS: Our report highlights an increased risk of acute arterial thromboembolic events in patients with reactive thrombocytosis, especially those undergoing surgery.
Subject(s)
Aspirin/administration & dosage , Blindness, Cortical , Brain Ischemia , Embolization, Therapeutic , Purpura, Thrombocytopenic, Idiopathic/complications , Spleen , Stroke , Thrombocytosis/drug therapy , Wounds, Nonpenetrating/therapy , Adult , Blindness, Cortical/diagnosis , Blindness, Cortical/drug therapy , Blindness, Cortical/etiology , Brain Ischemia/etiology , Brain Ischemia/physiopathology , Embolization, Therapeutic/adverse effects , Embolization, Therapeutic/methods , Female , Humans , Magnetic Resonance Imaging/methods , Multiple Trauma/complications , Multiple Trauma/surgery , Orthopedic Procedures/adverse effects , Platelet Aggregation Inhibitors/administration & dosage , Platelet Count/methods , Spleen/blood supply , Spleen/injuries , Splenic Artery/diagnostic imaging , Splenic Artery/pathology , Stroke/etiology , Stroke/physiopathology , Thrombocytosis/diagnosis , Thrombocytosis/etiology , Treatment OutcomeABSTRACT
This work presents a modified method to analyze selected pharmaceutical residues (clofibric acid, ibuprofen, carbamazepine, naproxen, ketoprofen and diclofenac) in water samples. Various solid-phase extraction cartridges were investigated. The newly developed Oasis HLB (polystyrene-divinylbenzene-N-vinyl pyrrolidone terpolymer) solid-phase extraction (SPE) cartridge provides the optimal sample extraction results. The analytes were then identified and quantitatively determined by gas chromatography-mass spectrometry (GC-MS) via on-line derivatization in the injection-port using a large-volume (10 microl) sample injection with tetrabutylammonium (TBA) salts. This injection-port derivatization technique provides sensitivity, fast and reproducible results for pharmaceutical residues analysis. Mass spectra of butylated derivatives and tentative fragmentation profiles are proposed. Molecular ions and some characteristic ions were used as the quantitation ions to obtain maximum detection sensitivity and specificity. The quantitation limits of these compounds ranged from 1.0 to 8.0 ng/l in 500 ml tap water samples. Recovery of these residues in spiked various water samples ranged from 50 to 108% while RSD ranged from 1 to 10%. The selected analytes were detected in concentrations of 30 to 420 ng/l in wastewater treatment plant effluent and river water samples.
Subject(s)
Drug Residues/analysis , Gas Chromatography-Mass Spectrometry/methods , Water Pollutants, Chemical/analysis , Reproducibility of Results , Sensitivity and SpecificityABSTRACT
BACKGROUND: The surface markers of mesenchymal stem cells (MSCs) of rabbits have been reported only sporadically. However, interest in the spinal fusion effect of MSCs has risen recently. The purpose of this research was to study the surface markers and spinal fusion effect of rabbit MSCs. RESULTS: Of our rabbit MSCs, 2% expressed CD14, CD29, and CD45, 1% expressed CD90 and 97% expressed CD44. These results implied the MSCs were negative for CD14, CD29, CD45, and CD90, but positive for CD44. The surgical results showed that satisfactory fusion occurred in 10 rabbits (83%) in the study group and unsatisfactory fusion in 2 (17%). In the control group, satisfactory fusion was found in 3 rabbits (25%) and unsatisfactory fusion in 9 (75%). Statistical analysis showed the study group had significantly better spinal fusion results than the control group. CONCLUSIONS: The surface markers of human and rabbit MSCs are not exactly the same. Rabbit MSCs do not have positive reactivity for CD29 and CD90, which are invariably present on human MSCs. The allogeneic undifferentiated rabbit MSCs were able to promote spinal fusion and did not induce an adverse immune response.
Subject(s)
Antigens, CD/immunology , Mesenchymal Stem Cells/cytology , Spinal Fusion , Animals , Flow Cytometry , Humans , Mesenchymal Stem Cells/immunology , RabbitsABSTRACT
The Arabidopsis LOB-domain (LBD) gene family is composed by 43 members divided in two classes based on amino acid conservation within the LOB-domain. The LOB domain is known to be responsible for DNA binding and protein-protein interactions. There is very little functional information available for most genes in the LBD family and many lbd single mutants do not exhibit conspicuous phenotypes. One plausible explanation for the limited loss-of-function phenotypes observed in this family is that LBD genes exhibit significant functional redundancy. Here we discuss an example of one phylogenetic subgroup of the LBD family, in which genes that are closely related based on phylogeny exhibit distinctly different expression patterns and do not have overlapping functions. We discuss the challenges of using phylogenetic analyses to predict redundancy in gene families.
Subject(s)
Arabidopsis Proteins/metabolism , Arabidopsis/metabolism , Arabidopsis/genetics , Arabidopsis Proteins/classification , Arabidopsis Proteins/genetics , Gene Expression Regulation, Plant/genetics , Gene Expression Regulation, Plant/physiology , Phylogeny , Plants, Genetically Modified/genetics , Plants, Genetically Modified/metabolism , Pollen/metabolismABSTRACT
BACKGROUND: Extracorporeal shock wave treatment (ESWT) has been proven effective in enhancing spinal fusion in a preliminary animal study. However, biomechanical tests were not performed. METHODS: All 12 rabbits in this study underwent decortication at the bilateral L5 and L6 transverse processes. Bone was chipped off and placed onto the intertransverse space. The rabbits were divided into two groups, a study group (n = 6) and a control group (n = 6). In the study group, the bilateral L5 and L6 transverse processes were treated with 1000 impulses of ESWT at 14 kilovolts (KV) (equivalent to 0.18 mJ/mm(2)) at 12 and 18 weeks after surgery. The control group rabbits did not undergo ESWT. A series of radiographic examinations on each rabbit were subsequently performed. All rabbits were killed at 21 weeks, and their spines were harvested for biomechanical tests. RESULTS: Radiographic examination showed 5 of the 6 rabbits in the study group had callus formation in the fusion masses. Biomechanical tests of the fusion segments showed that the mean flexion stiffness (with internal control) in the study group was 2.11 +/- 0.46, while that in the control group was 1.17 +/- 0.19. The mean extension stiffness (with internal control) in the study group was 1.70 +/- 0.39, while that in the control group was 1.23 +/- 0.29. Statistical analysis showed that the fusion segments in the study group had significantly better flexion and extension stiffness than those in the control group (p < 0.05). CONCLUSION: In this animal study, radiographic examinations showed that ESWT stimulated new bone growth. Biomechanical tests showed that ESWT significantly increased the flexion and extension stiffness of spinal fusion segments.
Subject(s)
High-Energy Shock Waves , Spinal Fusion , Animals , Biomechanical Phenomena , Lumbar Vertebrae/surgery , Male , RabbitsABSTRACT
BACKGROUND: Ostene, a synthetic water-soluble bone hemostatic agent, is commercially available. In the current study, we evaluated the systemic and local effects of this copolymer in a rabbit model. METHODS: Eighteen rabbits underwent creation of a bony defect at right iliac crest. These rabbits were then evenly divided into 3 groups. In group 1, the defect surfaces were treated with bone wax; in group 2, the defect surfaces were treated with Ostene; in group 3, the defect surfaces were not treated with anything. Then, the animals underwent blood examinations, including WBC count, CRP, and ESR at 0, 1, 3, and 6 weeks, and were killed at 6 weeks for histologic examination. Another 6 rabbits (group 4) underwent the same surgical treatment of group 2 animals but had blood examinations of BUN and creatinine. RESULTS: The blood examinations showed that the WBC count, CRP, and ESR of all the animals in the first 3 groups were within normal limits in the postoperative periods. Microscopic examinations demonstrated residual bone wax and fibrotic tissue at the defect surfaces in group 1 animals. However, there was no Ostene at the defect surfaces in group 2 animals. The groups 2 and 3 animals showed no fibrotic tissue at the defect surfaces. The group 4 animals showed normal serum levels of BUN and creatinine in the postoperative periods. CONCLUSION: Ostene is absorbable and induces no systemic inflammation (including acute renal damage) and local inflammation in animal bodies.
Subject(s)
Bone Diseases/surgery , Bone Substitutes/toxicity , Plastic Surgery Procedures/methods , Poloxamer/toxicity , Polymers/toxicity , Animals , Biomarkers/analysis , Biomarkers/metabolism , Bone Substitutes/chemistry , C-Reactive Protein/analysis , C-Reactive Protein/metabolism , Disease Models, Animal , Drug Combinations , Inflammation/chemically induced , Inflammation/physiopathology , Kidney Diseases/chemically induced , Kidney Diseases/physiopathology , Leukocyte Count , Male , Palmitates/therapeutic use , Poloxamer/chemistry , Polymers/chemistry , Rabbits , Waxes/therapeutic useABSTRACT
The normal development of lateral organs of the shoot requires the simultaneous repression of meristem-specific genes and the activation of organ-specific genes. ASYMMETRIC LEAVES2 (AS2) is required for the development of normal leaf shape and for the repression of KNOX genes in the leaf. AS2 is a member of the recently identified, plant-specific LATERAL ORGAN BOUNDARIES (LOB)-domain gene family. Expression of AS2 at high levels resulted in repression of the KNOX homeobox genes BREVIPEDICELLUS, KNAT2, and KNAT6 but not of the related SHOOT MERISTEMLESS gene. Overexpression of AS2 also led to a perturbation of normal adaxial-abaxial asymmetry in lateral organs, resulting in the replacement of abaxial cell types with adaxial cell types. These results indicate that AS2 is sufficient to induce adaxial cell fate and repress KNOX gene expression.