scholarly journals NOZZLE links proximal-distal and adaxial-abaxial pattern formation during ovule development in Arabidopsis thaliana

Development ◽  
2002 ◽  
Vol 129 (18) ◽  
pp. 4291-4300
Author(s):  
Sureshkumar Balasubramanian ◽  
Kay Schneitz
Keyword(s):  
Arabidopsis Thaliana ◽  
Transcription Factor ◽  
Pattern Formation ◽  
Vital Role ◽  
Regulatory Control ◽  
Homeodomain Protein ◽  
Ovule Development ◽  
Temporal Expression ◽  
Aberrant Testa Shape ◽  
Ap2 Domain

The ovules of Arabidopsis show polarity along the proximal-distal and the adaxial-abaxial axis. NOZZLE, a gene that encodes a novel protein and BELL1, encoding a homeodomain protein, play a vital role in pattern formation along the proximal-distal axis. INNER NO OUTER, which encodes a member of the YABBY family of transcription factors and SUPERMAN, encoding a zinc finger transcription factor, are essential for the establishment and maintenance of adaxial-abaxial polarity. To date, the co-ordination of patterning along these two axes is unclear. Here we show that NOZZLE plays a vital role in pattern formation along the adaxial-abaxial axis as well. We investigated the expression of INNER NO OUTER in various mutant backgrounds and have identified ABERRANT TESTA SHAPE and NOZZLE as spatial regulators of INNER NO OUTER expression. In addition, we show that NOZZLE and AINTEGUMENTA, which encodes an AP2 domain transcription factor, regulate the temporal expression of INNER NO OUTER and that BELL1 is essential for INNER NO OUTER expression. We further analysed the expression of BELL1 and AINTEGUMENTA in inner no outer mutants and show that the positive auto-regulatory control of INNER NO OUTER expression involves AINTEGUMENTA. Based on our results we propose a model for adaxial-abaxial pattern formation during ovule development. Our results indicate that NOZZLE plays a central role in patterning both the proximal-distal and the adaxial-abaxial axes. Furthermore, negatively regulating INO expression in a temporal manner, ensures that the adaxial-abaxial polarity is established after the specification of the chalaza, a proximal-distal axis pattern element. It therefore serves as a molecular link between these processes during ovule development in Arabidopsis thaliana.

scholarly journals Orchid Bsister gene PeMADS28 displays conserved function in ovule integument development

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Ching-Yu Shen ◽  
You-Yi Chen ◽  
Ke-Wei Liu ◽  
Hsiang-Chia Lu ◽  
Song-Bin Chang ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
Protein Interaction ◽  
Ectopic Expression ◽  
Flowering Plants ◽  
Complementation Test ◽  
Ovule Development ◽  
Mads Box ◽  
Temporal Expression ◽  
Protein Protein Interaction ◽  
Silique Length

AbstractThe ovules and egg cells are well developed to be fertilized at anthesis in many flowering plants. However, ovule development is triggered by pollination in most orchids. In this study, we characterized the function of a Bsister gene, named PeMADS28, isolated from Phalaenopsis equestris, the genome-sequenced orchid. Spatial and temporal expression analysis showed PeMADS28 predominantly expressed in ovules between 32 and 48 days after pollination, which synchronizes with integument development. Subcellular localization and protein–protein interaction analyses revealed that PeMADS28 could form a homodimer as well as heterodimers with D-class and E-class MADS-box proteins. In addition, ectopic expression of PeMADS28 in Arabidopsis thaliana induced small curled rosette leaves, short silique length and few seeds, similar to that with overexpression of other species’ Bsister genes in Arabidopsis. Furthermore, complementation test revealed that PeMADS28 could rescue the phenotype of the ABS/TT16 mutant. Together, these results indicate the conserved function of BsisterPeMADS28 associated with ovule integument development in orchid.

Dissection of sexual organ ontogenesis: a genetic analysis of ovule development in Arabidopsis thaliana

Development ◽  
1997 ◽  
Vol 124 (7) ◽  
pp. 1367-1376 ◽  
Author(s):  
K. Schneitz ◽  
M. Hulskamp ◽  
S.D. Kopczak ◽  
R.E. Pruitt
Keyword(s):  
Arabidopsis Thaliana ◽  
Pattern Formation ◽  
Large Scale ◽  
Control Level ◽  
Three Dimensional ◽  
Flowering Plant ◽  
Ovule Development ◽  
Cellular Processes ◽  
Mature Ovule ◽  
And Control

Understanding organogenesis remains a major challenge in biology. Specification, initiation, pattern formation and cellular morphogenesis, have to be integrated to generate the final three-dimensional architecture of a multicellular organ. To tackle this problem we have chosen the ovules of the flowering plant Arabidopsis thaliana as a model system. In a first step towards a functional analysis of ovule development, we performed a large-scale genetic screen and isolated a number of sterile mutants with aberrant ovule development, We provide indirect genetic evidence for the existence of proximal-distal pattern formation in the Arabidopsis ovule primordium. The analysis of the mutants has identified genes that act at an intermediate regulatory level and control initiation of morphogenesis in response to proximal-distal patterning. A second group of genes functions at a subordinate control level and regulates general cellular processes of morphogenesis. A large group of male and female sterile mutants shows defects restricted to early or late gametogenesis. In addition, we propose that the mature ovule obtains its overall curved shape by at least three different processes that act in only one domain of the ovule.

Pattern formation and growth during floral organogenesis: HUELLENLOS and AINTEGUMENTA are required for the formation of the proximal region of the ovule primordium in Arabidopsis thaliana

Development ◽  
1998 ◽  
Vol 125 (14) ◽  
pp. 2555-2563 ◽  
Author(s):  
K. Schneitz ◽  
S.C. Baker ◽  
C.S. Gasser ◽  
A. Redweik
Keyword(s):  
Arabidopsis Thaliana ◽  
Pattern Formation ◽  
Molecular Mechanisms ◽  
Embryo Sac ◽  
Typical Feature ◽  
Proximal Region ◽  
Ovule Development ◽  
Linear Arrangement ◽  
Floral Organogenesis ◽  
Temporal And Spatial

Our understanding of the molecular mechanisms that regulate and integrate the temporal and spatial control of cell proliferation during organ ontogenesis, particularly of floral organs, continues to be primitive. The ovule, the progenitor of the seed, of Arabidopsis thaliana has been used to develop an effective model system for the analysis of plant organogenesis. A typical feature of a generalized ovule is the linear arrangement of at least three distinct elements, the funiculus, chalaza and nucellus, along a proximal-distal axis. This pattern is supposed to be established during the early proliferative phase of ovule development. We provide genetic evidence that the young ovule primordium indeed is a composite structure. Two genes, HUELLENLOS and AINTEGUMENTA have overlapping functions in the ovule and differentially control the formation of the central and proximal elements of the primordium. The results indicate that proximal-distal pattern formation in the Arabidopsis ovule takes place in a sequential fashion, starting from the distal end. Furthermore, we show that HUELLENLOS also regulates the initiation and/or maintenance of integument and embryo sac ontogenesis and interestingly prevents inappropriate cell death in the young ovule.

NOZZLE regulates proximal-distal pattern formation, cell proliferation and early sporogenesis during ovule development in Arabidopsis thaliana

Development ◽  
2000 ◽  
Vol 127 (19) ◽  
pp. 4227-4238 ◽  
Author(s):  
S. Balasubramanian ◽  
K. Schneitz
Keyword(s):  
Cell Proliferation ◽  
Arabidopsis Thaliana ◽  
Pattern Formation ◽  
Initial Phase ◽  
Growth Control ◽  
Cell Number ◽  
Outer Function ◽  
Ovule Development ◽  
Floral Organogenesis ◽  
Downstream Target

With the characterisation of the NOZZLE gene we aim at a better understanding of the molecular and genetic mechanism underlying pattern formation and growth control during floral organogenesis. Our data indicate that NOZZLE links these processes during ovule development. In the ovule primordium NOZZLE plays a central role in the formation of the nucellus through antagonizing the activities of BELL, AINTEGUMENTA and INNER NO OUTER, all encoding putative transcription factors, in the prospective nucellar region. We provide evidence that NOZZLE and BELL are chalaza identity genes that share overlapping functions in establishing the prospective chalaza of the ovule. In addition, NOZZLE plays a role in controlling the cell number and by this means the length of the funiculus, again through antagonizing AINTEGUMENTA and INNER NO OUTER function. NOZZLE is also required for the development of the integuments. We show that during the initial phase of this process NOZZLE is transcriptionally regulated by AINTEGUMENTA and INNER NO OUTER. NOZZLE thus represents a downstream target of these two genes in the integument development pathway.

scholarly journals Pattern formation during early ovule development in Arabidopsis thaliana

2004 ◽  
Vol 273 (2) ◽  
pp. 321-334 ◽  
Author(s):  
Patrick Sieber ◽  
Jacqueline Gheyselinck ◽  
Rita Gross-Hardt ◽  
Thomas Laux ◽  
Ueli Grossniklaus ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
Pattern Formation ◽  
Ovule Development

scholarly journals Brassinosteroids repress the seed maturation program during the seed-to-seedling transition

2021 ◽  
Author(s):  
Jiuxiao Ruan ◽  
Huhui Chen ◽  
Tao Zhu ◽  
Yaoguang Yu ◽  
Yawen Lei ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
Transcription Factor ◽  
Abscisic Acid ◽  
Plant Hormone ◽  
Flowering Plants ◽  
Seed Maturation ◽  
Domain Protein ◽  
Abscisic Acid Insensitive3 ◽  
Underlying Mechanisms ◽  
Embryonic Structure

Abstract In flowering plants, repression of the seed maturation program is essential for the transition from the seed to the vegetative phase, but the underlying mechanisms remain poorly understood. The B3-domain protein VIVIPAROUS1/ABSCISIC ACID-INSENSITIVE3-LIKE 1 (VAL1) is involved in repressing the seed maturation program. Here we uncovered a molecular network triggered by the plant hormone brassinosteroid (BR) that inhibits the seed maturation program during the seed-to-seedling transition in Arabidopsis (Arabidopsis thaliana). val1-2 mutant seedlings treated with a BR biosynthesis inhibitor form embryonic structures, whereas BR signaling gain-of-function mutations rescue the embryonic structure trait. Furthermore, the BR-activated transcription factors BRI1-EMS-SUPPRESSOR 1 and BRASSINAZOLE-RESISTANT 1 bind directly to the promoter of AGAMOUS-LIKE15 (AGL15), which encodes a transcription factor involved in activating the seed maturation program, and suppress its expression. Genetic analysis indicated that BR signaling is epistatic to AGL15 and represses the seed maturation program by downregulating AGL15. Finally, we showed that the BR-mediated pathway functions synergistically with the VAL1/2-mediated pathway to ensure the full repression of the seed maturation program. Together, our work uncovered a mechanism underlying the suppression of the seed maturation program, shedding light on how BR promotes seedling growth.

scholarly journals Compromised Function of the Pancreatic Transcription Factor PDX1 in a Lineage of Desert Rodents

2021 ◽  
Author(s):  
Yichen Dai ◽  
Sonia Trigueros ◽  
Peter W. H. Holland
Keyword(s):  
Transcription Factor ◽  
Gene Conversion ◽  
Cell Function ◽  
Protein A ◽  
Gene Promoter ◽  
Homeodomain Protein ◽  
Β Cell ◽  
Desert Rodents ◽  
Biased Gene Conversion ◽  
Β Cell Function

AbstractGerbils are a subfamily of rodents living in arid regions of Asia and Africa. Recent studies have shown that several gerbil species have unusual amino acid changes in the PDX1 protein, a homeodomain transcription factor essential for pancreatic development and β-cell function. These changes were linked to strong GC-bias in the genome that may be caused by GC-biased gene conversion, and it has been hypothesized that this caused accumulation of deleterious changes. Here we use two approaches to examine if the unusual changes are adaptive or deleterious. First, we compare PDX1 protein sequences between 38 rodents to test for association with habitat. We show the PDX1 homeodomain is almost totally conserved in rodents, apart from gerbils, regardless of habitat. Second, we use ectopic gene overexpression and gene editing in cell culture to compare functional properties of PDX1 proteins. We show that the divergent gerbil PDX1 protein inefficiently binds an insulin gene promoter and ineffectively regulates insulin expression in response to high glucose in rat cells. The protein has, however, retained the ability to regulate some other β-cell genes. We suggest that during the evolution of gerbils, the selection-blind process of biased gene conversion pushed fixation of mutations adversely affecting function of a normally conserved homeodomain protein. We argue these changes were not entirely adaptive and may be associated with metabolic disorders in gerbil species on high carbohydrate diets. This unusual pattern of molecular evolution could have had a constraining effect on habitat and diet choice in the gerbil lineage.

scholarly journals Localisation and regulation of cholesterol transporters in the human hair follicle: mapping changes across the hair cycle

2021 ◽  
Author(s):  
Megan A. Palmer ◽  
Eleanor Smart ◽  
Iain S. Haslam
Keyword(s):  
Hair Follicle ◽  
Human Hair ◽  
Vital Role ◽  
Transport Proteins ◽  
Hair Follicles ◽  
Regulatory Control ◽  
Cholesterol Transport ◽  
Hair Cycle ◽  
Human Hair Follicle

AbstractCholesterol has long been suspected of influencing hair biology, with dysregulated homeostasis implicated in several disorders of hair growth and cycling. Cholesterol transport proteins play a vital role in the control of cellular cholesterol levels and compartmentalisation. This research aimed to determine the cellular localisation, transport capability and regulatory control of cholesterol transport proteins across the hair cycle. Immunofluorescence microscopy in human hair follicle sections revealed differential expression of ATP-binding cassette (ABC) transporters across the hair cycle. Cholesterol transporter expression (ABCA1, ABCG1, ABCA5 and SCARB1) reduced as hair follicles transitioned from growth to regression. Staining for free cholesterol (filipin) revealed prominent cholesterol striations within the basement membrane of the hair bulb. Liver X receptor agonism demonstrated active regulation of ABCA1 and ABCG1, but not ABCA5 or SCARB1 in human hair follicles and primary keratinocytes. These results demonstrate the capacity of human hair follicles for cholesterol transport and trafficking. Future studies examining the role of cholesterol transport across the hair cycle may shed light on the role of lipid homeostasis in human hair disorders.

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