Increase In Organ Size Research Articles

Exploring the Role of G Protein Expression in Sodium Butyrate-Enhanced Pancreas Development of Dairy Calves: A Proteomic Perspective.

The present study evaluated the effects of sodium butyrate (SB) supplementation on exocrine and endocrine pancreatic development in dairy calves. Fourteen male Holstein calves were alimented with either milk or milk supplemented with SB for 70 days. Pancreases were collected for analysis including staining, immunofluorescence, electron microscopy, qRT-PCR, Western blotting, and proteomics. Results indicated increased development in the SB group with increases in organ size, protein levels, and cell growth. There were also exocrine enhancements manifested as higher enzyme activities and gene expressions along with larger zymogen granules. Endocrine benefits included elevated gene expression, more insulin secretion, and larger islets, indicating a rise in β-cell proliferation. Proteomics and pathway analyses pinpointed the G protein subunit alpha-15 as a pivotal factor in pancreatic and insulin secretion pathways. Overall, SB supplementation enhances pancreatic development by promoting its exocrine and endocrine functions through G protein regulation in dairy calves.

Complete replacement of soybean meal with black soldier fly larvae meal in feeding program for broiler chickens from placement through to 49 days of age reduced growth performance and altered organs morphology

Black soldier fly larvae meal (BSFLM) is characterized with good nutritional and functional attributes. However, there is limited data on inclusion of BSFLM in broiler chicken rations from placement through to market weight. Therefore, we examined growth and organ responses of partial to complete replacement of soybean meal (SBM) with BSFLM in a practical feeding program. A total of 1,152 d-old male Ross × Ross 708 chicks were allocated to 48 pens and assigned one of six diets (n = 8). The diets were: a basal corn-SBM diet (0%BSFLM), 4 diets in which SBM in 0%BSFLM was replaced with BSFLM at 12.5, 25, 50, and 100% and a final diet (0 + AGP) in which 0%BSFLM was treated with coccidiostat (70 mg Narasin/kg) and antibiotic (55 mg Bacitracin Methylene Disalicylate/kg). For energy fortification, soy oil was used for 0%BSFLM diets and black soldier fly oil in the other diets. Body weight, feed intake (FI), BW gain (BWG), and mortality-corrected feed conversion ratio (FCR) were reported. Organ weights were recorded on d 24 and 49. On d 10, birds fed diets 12.5, 25, and 0 + AGP had higher BWG than birds fed diets 0, 50, and 100 (P < 0.01), and birds fed diet 100 had lower BWG than birds fed diets 0 or 50 (P < 0.01). Birds fed diets 50 and 100 had lower BWG than birds fed all other diets on d 24 and 49 (P < 0.05). Overall (d 0–49), BSFLM linearly (P < 0.01) decreased BW, BWG, and FI and increased FCR and mortality. The overall BWG of 50 and 100% BSFLM birds was 92 and 81% of birds fed 0%BSFLM, repectively and coresponding overall FI was 96 and 90%. An increase in gizzard, small intestine, pancreas, and liver relative weights were observed with increasing BSFLM inclusion (P < 0.01). The data indicated that lower levels of BSFLM could provide some growth-promoting effects commensurate to antibiotics in the starter phase. However, replacing SBM with greater amounts (≥50) of BSFLM reduced growth and increased organ size.

Reference Ranges of Age-Based Liver, Spleen, Pancreas, and Kidney Size in Conjunction with Waist Circumference in Children

Objective: In the initial phases of parenchymal diseases, the only finding would be an increase in organ size. We aimed to provide percentile charts of solid intraabdominal organ sizes by age for Turkish children on contrast-enhanced computed tomography images and reveal relative size ratios.Materials and Methods: A total of 800 abdominal computed tomography examinations of otherwise healthy children (468 males, 332 females) were enrolled. The transverse diameter and lengths of both liver lobes, the thickness of the pancreas, width and length of the spleen, and anteroposterior diameters and lengths of both kidneys were measured. Differences in mean diameters among ages were compared with the analysis of variance test. Pearson’s correlation was assessed to depict the association of size with age and waist circumference.Results: Percentile charts for all measured size parameters that presented statistically significant positive correlations with age and waist circumference were provided. There were constant ratios of the right liver lobe to the left liver lobe (1.9 ± 0.37), right liver lobe to the right kidney (1.56 ± 0.26), left to the right kidney (1.03 ± 0.09), and spleen to the left kidney (1 ± 0.2) lengths in every age groups. Age (years)-dependant regression equation for waist circumference (mm) was depicted as “22 × age + 408.”Conclusion: Age-based percentile charts of solid intraabdominal organ diameters along with relative organ size ratios were provided.

QUANTITATIVE MORPHOMETRIC INDICATORS IN THE KIDNEYS OF LAYING HENS AND REPLACEMENT CHICKENS WITH UROLITHIASIS

The article provides data on the histological and morphometric examination of the kidneys of chickens in the spontaneous course of urolithiasis. With urolithiasis in chickens, a sharp increase in organ size is macroscopically noted. Histological examination revealed that the process of urates sedimentation in the parenchyma of the kidneys of birds begins at the age of 126 days. In this case, calcium urates take the form of basophilic crystal structures. Urolithiasis in hens and replacement chickens leads to severe atrophy of the vascular glomeruli and tubules and, as a result, to sclerotization of the organ.

Splenomegaly in Children and Adolescents.

In contrast to other lymphoid tissues making up the immune system, the spleen as its biggest organ is directly linked into the blood circulation. Beside its main task to filter out microorganism, proteins, and overaged or pathologically altered blood cells, also humoral and cellular immune responses are initiated in this organ. The spleen is not palpable during a physical examination in most but not all healthy patients. A correct diagnosis of splenomegaly in children and adolescents must take into account age-dependent size reference values. Ultrasound examination is nowadays used to measure the spleen size and to judge on reasons for morphological alterations in associated with an increase in organ size. An enormous amount of possible causes has to be put in consideration if splenomegaly is diagnosed. Among these are infectious agents, hematologic disorders, infiltrative diseases, hyperplasia of the white pulp, congestion, and changes in the composition and structure of the white pulp by immunologically mediated diseases. This review attempts to discuss a comprehensive list of differential diagnoses to be considered clinically in children and young adolescents.

Genome-wide analysis of the AINTEGUMENTA-like (AIL) transcription factor gene family in pumpkin (Cucurbita moschata Duch.) and CmoANT1.2 response in graft union healing

AINTEGUMENTA-like (AIL) proteins are members of the APETALA 2/ETHYLENE RESPONSE FACTOR (AP2/ERF) domain family of transcription factors involved in plant growth, development, and abiotic stress responses. However, the biological functions of AIL members in pumpkin (Cucurbita moschata Duch.) remain unknown. In this study, we identified 12 AIL genes in the pumpkin genome encoding proteins predicted to be localized in the nucleus. Phylogenetic analysis showed that the AIL gene family could be classified into six major subfamilies, with each member encoding two AP2/ERF domains separated by a linker region. CmoAIL genes were expressed at varying levels in the examined tissues, and CmoANT genes showed different expression patterns under auxin (IAA), 1-naphthylphthalamic acid (NPA), and abscisic acid (ABA) treatments. Ectopic overexpression of CmoANT1.2 in Arabidopsis increased organ size and promoted growth of grafted plants by accelerating graft union formation. However, there was no significant difference at the graft junction for WT/WT and WT/ANT under IAA or NPA treatments. Taken together, the results of this study provide critical information about CmoAIL genes and their encoded proteins, and suggest future work should investigate the functions of CmoANT1.2 in the grafting process in pumpkin.

Asymmetrical effects of autopolyploidization on organ size and gene expression in Brassica rapa and B. oleracea

Autopolyploidization usually accompanied with the enlargement of single organs or even the whole plant. The potential mechanism is still unclear. Here, we investigated the genome heterozygosity and compared the effect of polyploidization on organ size and global gene expression of two Brassica diploids, B. rapa and B. oleracea. Both vegetative and reproductive organs of enlarged size were observed for the aotutetraploid of B. rapa. In sharp contrast, the B. oleracea aotutetraploid did not show increased organ size except for the seeds. Transcriptome analysis in young silique wall revealed significant more differentially expressed genes (DEGs) between autotetraploid and diploid in B. rapa than those in B. oleracea. These DEGs were distributed randomly on chromosomes and did not show association with those heterozygosity regions. Several genes involved in cell wall biosynthesis were significantly up-regulated in aotutetraploid B. rapa which was well consist with the enlarged siliques. Interestingly, two significantly down-regulated FLOWERING LOCUS T (FT) genes were found in silique wall of autotetraploid B. oleracea. These findings indicated autopolyploidization consequence on organ size and gene expression in Brassica was species-specific and organ-specific which might be under genetic control related to the genome structure and composition.

GmKIX8-1 regulates organ size in soybean and is the causative gene for the major seed weight QTL qSw17-1.

Seed weight is one of the most important agronomic traits in soybean for yield improvement and food production. Several quantitative trait loci (QTLs) associated with the trait have been identified in soybean. However, the genes underlying the QTLs and their functions remain largely unknown. Using forward genetic methods and CRISPR/Cas9 gene editing, we identified and characterized the role of GmKIX8-1 in the control of organ size in soybean. GmKIX8-1 belongs to a family of KIX domain-containing proteins that negatively regulate cell proliferation in plants. Consistent with this predicted function, we found that loss-of-function GmKIX8-1 mutants showed a significant increase in the size of aerial plant organs, such as seeds and leaves. Likewise, the increase in organ size is due to increased cell proliferation, rather than cell expansion, and increased expression of CYCLIN D3;1-10. Lastly, molecular analysis of soybean germplasms harboring the qSw17-1 QTL for the big-seeded phenotype indicated that reduced expression of GmKIX8-1 is the genetic basis of the qSw17-1 phenotype.

Unreduced Male Gamete Formation in Cymbidium and Its Use for Developing Sexual Polyploid Cultivars.

Polyploidy plays an important role in crop improvement. Polyploid plants, particularly those produced through unreduced gametes (2n gametes), show increased organ size, improved buffering capacity for deleterious mutations, and enhanced heterozygosity and heterosis. Induced polyploidy has been widely used for improving floriculture crops, however, there are few reported sexual polyploid plants in the floriculture industry. This study evaluated nine cultivars of Cymbidium Swartz and discovered that 2n male gametes occurred in this important orchid. Depending on cultivars, 2n male gamete formation frequencies varied from 0.15 to 4.03%. Interspecific hybrids generally produced more 2n male gametes than traditional cultivars. To generate sexual polyploid plants, seven pairs of crosses were made, which produced five triploid and two tetraploid hybrids. Two triploid hybrids were evaluated for in vitro regeneration and growth characteristics. Compared to the diploid parents, the triploids were more easily regenerated through rhizomes or protocorms, and regenerated plants had improved survival rates after transplanting to the greenhouse. Furthermore, the sexual polyploid plants had more compact growth style, produced fragrant flowers, and demonstrated heterosis in plant growth. Through this study, a reliable protocol for selection of appropriate parents for 2n gamete production, ploidy level evaluation, in vitro culture of polyploid progenies, and development of new polyploid cultivars was established. Our study with Cymbidium suggests that the use of 2n gametes is a viable approach for improving floriculture crops.

Rice Big Grain 1promotes cell division to enhance organ development, stress tolerance and grain yield

SummaryGrain/seed yield and plant stress tolerance are two major traits that determine the yield potential of many crops. In cereals, grain size is one of the key factors affecting grain yield. Here, we identify and characterize a newly discovered gene Rice Big Grain 1 (RBG1) that regulates grain and organ development, as well as abiotic stress tolerance. Ectopic expression of RBG1 leads to significant increases in the size of not only grains but also other major organs such as roots, shoots and panicles. Increased grain size is primarily due to elevated cell numbers rather than cell enlargement. RBG1 is preferentially expressed in meristematic and proliferating tissues. Ectopic expression of RBG1 promotes cell division, and RBG1 co‐localizes with microtubules known to be involved in cell division, which may account for the increase in organ size. Ectopic expression of RBG1 also increases auxin accumulation and sensitivity, which facilitates root development, particularly crown roots. Moreover, overexpression of RBG1 up‐regulated a large number of heat‐shock proteins, leading to enhanced tolerance to heat, osmotic and salt stresses, as well as rapid recovery from water‐deficit stress. Ectopic expression of RBG1 regulated by a specific constitutive promoter, GOS2, enhanced harvest index and grain yield in rice. Taken together, we have discovered that RBG1 regulates two distinct and important traits in rice, namely grain yield and stress tolerance, via its effects on cell division, auxin and stress protein induction.

Characterization of the visceral and neuronal phenotype of 4L/PS-NA mice modeling Gaucher disease.

Gaucher disease is caused by a deficiency in glucocerebrosidase that can result in non-neuronal as well as neuronal symptoms. Common visceral symptoms are an increased organ size, specifically of the spleen, and glucosylceramide as well as glucosylsphingosine substrate accumulations as a direct result of the glucocerebrosidase deficiency. Neuronal symptoms include motor deficits and strong alterations in the cerebellum. To evaluate the effect of new compounds for the treatment of this devastating disease, animal models are needed that closely mimic the human phenotype. The 4L/PS-NA mouse as model of Gaucher disease is shown to present reduced glucocerebrosidase activity similar to human cases but an in-depth characterization of the model was still not performed. We therefore analyzed 4L/PS-NA mice for visceral alterations, motor deficits and also neuronal changes like glucocerebrosidase activity, substrate levels and neuroinflammation. A special focus was set at pathological changes of the cerebellum. Our results show that 4L/PS-NA mice have strongly enlarged visceral organs that are infiltrated by enlarged leukocytes and macrophages. Furthermore, animals present strong motor deficits that are accompanied by increased glucosylceramide and glucosylsphingosine levels in the brain, astrocytosis and activated microglia in the cortex and hippocampus as well as reduced calbindin levels in the cerebellum. The latter was directly related to a strong Purkinje cell loss. Our results thus provide a detailed characterization of the 4L/PS-NA mouse model over age showing the translational value of the model and validating its usefulness for preclinical efficiency studies to evaluate new compounds against Gaucher disease.

Assessment of the state of the reproductive system of males of Northern sled dog breeds in a kennel

Due to the increased interest in sledding in dogs, the assessment of their reproductive function, in particular breeding males, is also relevant at the present time. In the course of the work, the prostate condition was assessed in breeding working animals in a kennel, as well as the quality of sperm in working dogs of different ages, as well as in non-working groups. The results showed that in 16.8% of males the prostate is not enlarged, the echostructure is uniform, the contours are even, and the echogenicity is normal. A slight increase in the organ without structural changes is observed in 42% of the examined animals and the same number of dogs (42%), have echostructural changes and increased organ size. Prostate enlargement in most of the examined males of the kennel may be associated with the crowding of their content, as well as the presence of bitches in neighboring enclosures. When assessing semen quality in workers of different age groups and non-group males in various time intervals at different intensity of physical activity. it is noted that the stability of sperm quality identified in males outside of the group, while animals in the system having both long and short-term physical load sperm quality is subject to considerable fluctuations. Thus, under intense load, the sperm quality indicators correspond to the reference values in animals of all groups, while during the long period of rest, working sled dogs have a significant decrease in the quality of sperm, which negatively affects their fertility.

Acute liver injury in the course of lymphoplasmacytic lymphoma

Abstract Non-Hodgkin lymphomas are malignant neoplasms whose incidence rates increase each year. These also include neoplasms rare in the general population. The present case report described a patient with lymphoplasmacytic lymphoma (LPL) and rapid liver damage. In most cases, infiltration of the liver is rare in advanced stages of hematopoietic malignancies when hepatomegaly, cholestatic jaundice and organ failure are observed. The patient’s history includes non-specific abdominal pain that was accompanied by general symptoms such as nocturnal hyperhidrosis, subfibrile temperature and fever, as well as weight loss. The above complaints aggravate with an increase in organ size. The laboratory findings initially demonstrated moderately elevated concentrations of transaminases. In our case, the baseline biochemical indices of liver function were found to be normal. During the next days of hospitalisation, the features of liver damage intensified and were accompanied by liver failure. The gold diagnostic standard is a biopsy of the bone marrow and the organ affected. Since the patient’s condition deteriorated and liver failure developed, the diagnosis was established based on trephine biopsy of the bone marrow. Chemotherapy was implemented; despite the treatment applied, the patient’s clinical condition did not improve. Two months after the onset of first symptoms the patient died.

Identification and Functional Characterization of Squamosa Promoter Binding Protein-Like Gene TaSPL16 in Wheat (Triticum aestivum L.).

Wheat (Triticum aestivum L.) is one of the most important crops in the world. Squamosa promoter binding protein-like (SPL) proteins are plant-specific transcript factors and play critical roles in plant growth and development. The functions of many SPL gene family members were well characterized in Arabidopsis and rice, in contrast, research on wheat SPL genes is lagging behind. In this study, we cloned and characterized TaSPL16, an orthologous gene of rice OsSPL16, in wheat. Three TaSPL16 homoeologs are located on the short arms of chromosome 7A, 7B, and 7D, and share more than 96% sequence identity with each other. All the TaSPL16 homoeologs have three exons and two introns, with a miR156 binding site in their last exons. They encode putative proteins of 407, 409, and 414 amino acid residues, respectively. Subcellular localization showed TaSPL16 distribution in the cell nucleus, and transcription activity of TaSPL16 was validated in yeast. Analysis of the spatiotemporal expression profile showed that TaSPL16 is highly expressed in young developing panicles, lowly expressed in developing seeds and almost undetectable in vegetative tissues. Ectopic expression of TaSPL16 in Arabidopsis causes a delay in the emergence of vegetative leaves (3–4 days late), promotes early flowering (5–7 days early), increases organ size, and affects yield-related traits. These results demonstrated the regulatory roles of TaSPL16 in plant growth and development as well as seed yield. Our findings enrich the existing knowledge on SPL genes in wheat and provide valuable information for further investigating the effects of TaSPL16 on plant architecture and yield-related traits of wheat.

Construction of genetic linkage map and genome dissection of domestication-related traits of moth bean (Vigna aconitifolia), a legume crop of arid areas.

The moth bean (Vigna aconitifolia), possibly the most primitive crop of the genus Vigna, is a highly drought- and heat-resistant legume grown in arid areas. Moth bean domestication involved phenotypic changes, including reduction of seed dormancy and pod shattering, increased organ size, and earlier flowering and maturity. However, the genetics of the domestication process in moth bean is not known. In this study, we constructed a genetic linkage map for moth bean and used the map to identify quantitative trait loci (QTL) for domestication-related traits of an F2 population of 188 individuals produced from a cross of wild moth bean (TN67) and cultivated moth bean (ICPMO056). The genetic linkage map comprised 11 linkage groups (LG) of 172 simple sequence repeatmarkers and spanned a total length of 1016.8centiMorgan (cM), with an average marker distance of 7.34cM. A comparative genome analysis showed high genome synteny between moth bean and mungbean (Vigna radiata), adzuki bean (Vigna angularis), rice bean (Vigna umbellata), and yardlong bean (Vigna unguiculata). In total, 50 QTLs and 3 genes associated with 20 domestication-related traits were identified. Most of the QTLs belonged to five LGs (1, 2, 4, 7, and 10). Key traits related to domestication such as seed dormancy and pod shattering were controlled by large-effect QTLs (PVE > 20%) with one or two minor QTLs, whereas all other traits were controlled by one-seven minor QTLs, apart from seed weight, which was controlled by one major and seven minor QTLs. These results suggest that a small number of mutations with large phenotypic effects have contributed to the domestication of the moth bean. Comparative analysis of QTLs with related Vigna crops revealed that there are several domestication-related large-effect QTLs that had not been used in moth bean domestication. This study provides a basic genetic map and identified genome regions associated with domestication-related traits, which will be useful for the genetic improvement of the moth bean and related Vigna species.

Robust increase of leaf size by Arabidopsis thaliana GRF3-like transcription factors under different growth conditions

An increase in crop yield is essential to reassure food security to meet the accelerating global demand. Several genetic modifications can increase organ size, which in turn might boost crop yield. Still, only in a few cases their performance has been evaluated under stress conditions. MicroRNA miR396 repress the expression of GROWTH-REGULATING FACTOR (GRF) genes that codes for transcription factors that promote organ growth. Here, we show that both Arabidopsis thaliana At-GRF2 and At-GRF3 genes resistant to miR396 activity (rGRF2 and rGRF3) increased organ size, but only rGRF3 can produce this effect without causing morphological defects. Furthermore, introduction of At-rGRF3 in Brassica oleracea can increase organ size, and when At-rGRF3 homologs from soybean and rice are introduced in Arabidopsis, leaf size is also increased. This suggests that regulation of GRF3 activity by miR396 is important for organ growth in a broad range of species. Plants harboring rGRF3 have larger leaves also under drought stress, a condition that stimulates miR396 accumulation. These plants also showed an increase in the resistance to virulent bacteria, suggesting that the size increment promoted by rGRF3 occurs without an obvious cost on plant defenses. Our findings indicate that rGRF3 can increase plant organ size under both normal and stress conditions and is a valuable tool for biotechnological applications.

Postnatal Exocrine Pancreas Growth by Cellular Hypertrophy Correlates with a Shorter Lifespan in Mammals

Developmental processes in different mammals are thought to share fundamental cellular mechanisms. We report a dramatic increase in cell size during postnatal pancreas development in rodents, accounting for much of the increase in organ size after birth. Hypertrophy of pancreatic acinar cells involves both higher ploidy and increased biosynthesis per genome copy; is maximal adjacent to islets, suggesting endocrine to exocrine communication; and is partly driven by weaning-related processes. In contrast to the situation in rodents, pancreas cell size in humans remains stable postnatally, indicating organ growth by pure hyperplasia. Pancreatic acinar cell volume varies 9-fold among 24 mammalian species analyzed, and shows a striking inverse correlation with organismal lifespan. We hypothesize that cellular hypertrophy is a strategy for rapid postnatal tissue growth, entailing life-long detrimental effects.

Identification of QTL controlling domestication-related traits in cowpea (Vigna unguiculata L. Walp)

Cowpea (Vigna unguiculata L. Walp) is a warm-season legume with a genetically diverse gene-pool composed of wild and cultivated forms. Cowpea domestication involved considerable phenotypic changes from the wild progenitor, including reduction of pod shattering, increased organ size, and changes in flowering time. Little is known about the genetic basis underlying these changes. In this study, 215 recombinant inbred lines derived from a cross between a cultivated and a wild cowpea accession were used to evaluate nine domestication-related traits (pod shattering, peduncle length, flower color, days to flowering, 100-seed weight, pod length, leaf length, leaf width and seed number per pod). A high-density genetic map containing 17,739 single nucleotide polymorphisms was constructed and used to identify 16 quantitative trait loci (QTL) for these nine traits. Based on annotations of the cowpea reference genome, genes within these regions are reported. Four regions with clusters of QTL were identified, including one on chromosome 8 related to increased organ size. This study provides new knowledge of the genomic regions controlling domestication-related traits in cowpea as well as candidate genes underlying those QTL. This information can help to exploit wild relatives in cowpea breeding programs.

Claudin-18-mediated YAP activity regulates lung stem and progenitor cell homeostasis and tumorigenesis.

Claudins, the integral tight junction (TJ) proteins that regulate paracellular permeability and cell polarity, are frequently dysregulated in cancer; however, their role in neoplastic progression is unclear. Here, we demonstrated that knockout of Cldn18, a claudin family member highly expressed in lung alveolar epithelium, leads to lung enlargement, parenchymal expansion, increased abundance and proliferation of known distal lung progenitors, the alveolar epithelial type II (AT2) cells, activation of Yes-associated protein (YAP), increased organ size, and tumorigenesis in mice. Inhibition of YAP decreased proliferation and colony-forming efficiency (CFE) of Cldn18-/- AT2 cells and prevented increased lung size, while CLDN18 overexpression decreased YAP nuclear localization, cell proliferation, CFE, and YAP transcriptional activity. CLDN18 and YAP interacted and colocalized at cell-cell contacts, while loss of CLDN18 decreased YAP interaction with Hippo kinases p-LATS1/2. Additionally, Cldn18-/- mice had increased propensity to develop lung adenocarcinomas (LuAd) with age, and human LuAd showed stage-dependent reduction of CLDN18.1. These results establish CLDN18 as a regulator of YAP activity that serves to restrict organ size, progenitor cell proliferation, and tumorigenesis, and suggest a mechanism whereby TJ disruption may promote progenitor proliferation to enhance repair following injury.

HAWAIIAN SKIRT controls size and floral organ number by modulating CUC1 and CUC2 expression.

The Arabidopsis thaliana F-box gene HAWAIIAN SKIRT (HWS) affects organ growth and the timing of floral organ abscission. The loss-of-function hws-1 mutant exhibits fused sepals and increased organ size. To understand the molecular mechanisms of HWS during plant development, we mutagenized hws-1 seeds with ethylmethylsulphonate (EMS) and screened for mutations suppressing hws-1 associated phenotypes. We isolated the shs1/hws-1 (suppressor of hws-1) mutant in which hws-1 sepal fusion phenotype was suppressed. The shs1/hws-1 mutant carries a G→A nucleotide substitution in the MIR164 binding site of CUP-SHAPED COTYLEDON 1 (CUC1) mRNA. CUC1 and CUP-SHAPED COTYLEDON 2 (CUC2) transcript levels were altered in shs1, renamed cuc1-1D, and in hws-1 mutant. Genetic interaction analyses using single, double and triple mutants of cuc1-1D, cuc2-1D (a CUC2 mutant similar to cuc1-1D), and hws-1, demonstrate that HWS, CUC1 and CUC2 act together to control floral organ number. Loss of function of HWS is associated with larger petal size due to alterations in cell proliferation and mitotic growth, a role shared with the CUC1 gene.