Abnormal cell divisions in leaf primordia caused by the expression of the rice homeobox gene

1996 ◽  
Vol 251 (1) ◽  
pp. 13 ◽  
Author(s):  
Yutaka Sato ◽  
Masanori Tamaoki ◽  
Taka Murakami ◽  
Naoki Yamamoto ◽  
Yuriko Kano-Murakami ◽  
...  
Keyword(s):  
Homeobox Gene ◽  
Leaf Primordia ◽  
Abnormal Cell ◽  
Cell Divisions

scholarly journals Extended expression of MaKN1 contributes to the leaf morphology in aquatic forms of Myriophyllum aquaticum

Botany ◽  
2015 ◽  
Vol 93 (9) ◽  
pp. 611-621
Author(s):  
M.D. Shafiullah ◽  
Christian R. Lacroix
Keyword(s):  
Apical Meristem ◽  
Leaf Morphology ◽  
Expression Patterns ◽  
Homeobox Gene ◽  
Leaf Primordia ◽  
Leaf Primordium ◽  
Myriophyllum Aquaticum ◽  
Knox Gene ◽  
Leaf Morphogenesis

Myriophyllum aquaticum (Vell.) Verdc. is heterophyllous in nature with highly dissected simple leaves consisting of several lobes. KNOX (KNOTTED1-LIKE HOMEOBOX) genes are believed to have played an important role in the evolution of leaf diversity. Up-regulation of KNOX during leaf primordium initiation can lead to leaf dissection in plants with simple leaves and, if overexpressed, can produce ectopic meristems on leaves. A previous study on KNOX gene expression in the aerial form of this species showed that this gene is expressed in the shoot apical meristem (SAM), as well as in leaf primordia P0 to P8. Based on these results, it was hypothesized that the prolonged expression of the MaKN1 (Myriophyllum aquaticum Knotted1-like homeobox) gene beyond P8, might play an important role in the generation of more lobes, longer lobes, and hydathode formation in the aquatic leaves of M. aquaticum. The technique of in situ hybridization was carried out using a previously sequenced 300 bp fragment of MaKN1 to determine the expression patterns of this gene in the shoot of aquatic forms of the plant. Expression patterns of MaKN1 revealed that the SAM and leaf primordia of aquatic forms of M. aquaticum at levels P0 (youngest) to P4 were distributed throughout these structures. The level of expression of this MaKN1 gene progressively became more localized to lobes in older leaf primordia (levels P5 to P12). Previous studies of aerial forms of this plant showed MaKN1 expression until P8. Our results with aquatic forms show that the highly dissected leaf morphology in aquatic forms was the result of the prolonged expression of MaKN1 beyond P8. This resulted in the formation of elongated and slightly more numerous lobes, and hydathodes in aquatic forms. These findings support the view that KNOX genes are important developmental regulators of leaf morphogenesis and have played an important role in the evolution of leaf forms in the plant kingdom.

scholarly journals A fern WUSCHEL-RELATED HOMEOBOX gene functions in both gametophyte and sporophyte generations

2019 ◽  
Vol 19 (1) ◽  
Author(s):  
Christopher E. Youngstrom ◽  
Lander F. Geadelmann ◽  
Erin E. Irish ◽  
Chi-Lien Cheng
Keyword(s):  
Stem Cells ◽  
Lateral Roots ◽  
Homeobox Gene ◽  
Genetic Networks ◽  
Land Plants ◽  
Seed Plants ◽  
Wild Type ◽  
Cell Fates ◽  
Cell Divisions ◽  
Gene Functions

Abstract Background Post-embryonic growth of land plants originates from meristems. Genetic networks in meristems maintain the stem cells and direct acquisition of cell fates. WUSCHEL-RELATED HOMEOBOX (WOX) transcription factors involved in meristem networks have only been functionally characterized in two evolutionarily distant taxa, mosses and seed plants. This report characterizes a WOX gene in a fern, which is located phylogenetically between the two taxa. Results CrWOXB transcripts were detected in proliferating tissues, including gametophyte and sporophyte meristems of Ceratopteris richardii. In addition, CrWOXB is expressed in archegonia but not the antheridia of gametophytes. Suppression of CrWOXB expression in wild-type RN3 plants by RNAi produced abnormal morphologies of gametophytes and sporophytes. The gametophytes of RNAi lines produced fewer cells, and fewer female gametes compared to wild-type. In the sporophyte generation, RNAi lines produced fewer leaves, pinnae, roots and lateral roots compared to wild-type sporophytes. Conclusions Our results suggest that CrWOXB functions to promote cell divisions and organ development in the gametophyte and sporophyte generations, respectively. CrWOXB is the first intermediate-clade WOX gene shown to function in both generations in land plants.

The initial protrusion of a leaf primordium can form without concurrent periclinal cell divisions

1971 ◽  
Vol 49 (9) ◽  
pp. 1601-1603 ◽  
Author(s):  
Donald E. Foard
Keyword(s):  
Gamma Rays ◽  
Shoot Apex ◽  
Cell Layer ◽  
Fold Increase ◽  
Leaf Primordia ◽  
Leaf Primordium ◽  
Initial Number ◽  
Wheat Grains ◽  
Cell Divisions ◽  
Number Of Cells

The view that periclinal cell divisions cause the initial protrusion of a leaf primordium may be tested by using ionizing radiation to prevent cell divisions without preventing growth. After receiving 800 krad of gamma rays, wheat grains containing embryos with three leaf primordia produce seedlings in which a fourth protrusion of the shoot apex forms unaccompanied by cell divisions. This protrusion without periclinal divisions occurs in the same phyllotactic position as that of the fourth leaf primordium in which periclinal divisions occur. In addition to proper phyllotactic position, the protrusion without cell divisions is formed by the outermost cell layer, as is the initial protrusion of a typical leaf primordium of wheat; moreover, the initial number of cells involved is the same in both kinds of protrusions. Therefore the fourth protrusion in seedlings from irradiated grain is interpreted as the initial protrusion of a leaf primordium that formed without periclinal cell divisions. Measured along the axis of greatest extension, the protrusions without cell divisions represent about a four- to eight-fold increase over the anticlinal dimension of the surface-cell layer in the embryo. These protrusions do not develop further. The absence of cell divisions limits the extent of primordial growth, but does not prevent its inception. Periclinal cell divisions do not cause the initial protrusion of a leaf primordium.

Centrosome-centriole abnormalities are markers for abnormal cell divisions and cancer in the transgenic adenocarcinoma mouse prostate (TRAMP) model

2000 ◽  
Vol 92 (5) ◽  
pp. 331-340 ◽  
Author(s):  
Heide Schatten ◽  
Allison Wiedemeier ◽  
Meghan Taylor ◽  
Dennis B. Lubahn ◽  
Norman M. Greenberg ◽  
...  
Keyword(s):  
Abnormal Cell ◽  
Cell Divisions ◽  
Mouse Prostate

scholarly journals The sequence of cell divisions in the I tunic layer of Actinidia arguta Planch in light of the development of twin cell complexes

2014 ◽  
Vol 55 (2) ◽  
pp. 171-179 ◽  
Author(s):  
Zofia Puławska
Keyword(s):  
Leaf Primordia ◽  
Cell Complexes ◽  
Actinidia Arguta ◽  
Cell Divisions ◽  
Meristematic Activity ◽  
Mother Cells

In <em>Actinidia arguta</em>, the I tunc layer is formed by four cell complexes which descend from single initials. These initials are positioned in a corner of their complex, around the meristem axis. The meristematic activity of the I tunic layer depends on the formative divisions of the initials; the entire I tunic layer above the youngest leaf primordia is formed during the time the initials undergo only 4-8 divisions. In light of the development of the twin cell complexes. it is impossible for cells to be displaced from the I tunic layer into the meristem. The supposition is set forth that the impermanent. mericlinal sectors on variegated perinclinal chimeras develop due to periclinal cleavages within the subcomplexes which derive from tissue mother cells. Whereas. the cell initials do not undergo periclinal divisions and are not displaced.

Live birth potential of good morphology and vitrified blastocysts presenting abnormal cell divisions

2017 ◽  
Vol 17 (2) ◽  
pp. 144-150 ◽  
Author(s):  
Antonino Azzarello ◽  
Thomas Hoest ◽  
Anders Hay-Schmidt ◽  
Anne Lis Mikkelsen
Keyword(s):  
Live Birth ◽  
Abnormal Cell ◽  
Cell Divisions

scholarly journals Loss-of-function mutations in the maize homeobox gene, knotted1, are defective in shoot meristem maintenance

Development ◽  
1997 ◽  
Vol 124 (16) ◽  
pp. 3045-3054 ◽  
Author(s):  
R.A. Kerstetter ◽  
D. Laudencia-Chingcuanco ◽  
L.G. Smith ◽  
S. Hake
Keyword(s):  
Homeobox Gene ◽  
Leaf Primordia ◽  
Shoot Meristem ◽  
Loss Of Function ◽  
Floral Organs ◽  
Leaf Phenotype ◽  
Lateral Organ ◽  
Recessive Mutant ◽  
Meristem Maintenance ◽  
Shoot Meristems

The product of the maize homeobox gene, knotted1 (kn1), localizes to the nuclei of cells in shoot meristems, but is absent from portions of the meristem where leaf primordia or floral organs initiate. Recessive mutant alleles of kn1 were obtained by screening for loss of the dominant leaf phenotype in maize. Mutant kn1 alleles carrying nonsense, splicing and frame shift mutations cause severe inflorescence and floral defects. Mutant tassels produce fewer branches and spikelets. Ears are often absent, and when present, are small with few spikelets. In addition, extra carpels form in female florets and ovule tissue proliferates abnormally. Less frequently, extra leaves form in the axils of vegetative leaves. These mutations reveal a role for kn1 in meristem maintenance, particularly as it affects branching and lateral organ formation.

The homeobox gene NTH23 of tobacco is expressed in the basal region of leaf primordia

1998 ◽  
Vol 1399 (2-3) ◽  
pp. 203-208 ◽  
Author(s):  
Naoki Sentoku ◽  
Masanori Tamaoki ◽  
Asuka Nishimura ◽  
Makoto Matsuoka
Keyword(s):  
Homeobox Gene ◽  
Leaf Primordia ◽  
Basal Region

scholarly journals Generation of medial and lateral dorsal body domains by the pannier gene of Drosophila

Development ◽  
2000 ◽  
Vol 127 (18) ◽  
pp. 3971-3980 ◽  
Author(s):  
M. Calleja ◽  
H. Herranz ◽  
C. Estella ◽  
J. Casal ◽  
P. Lawrence ◽  
...  
Keyword(s):  
Transcription Factor ◽  
General Feature ◽  
Homeobox Gene ◽  
Body Plan ◽  
Cardiac Cells ◽  
Dorsal Region ◽  
Adhesion Properties ◽  
Cell Divisions ◽  
Gata Transcription Factor ◽  
Thoracic And Abdominal

The pannier (pnr) gene encodes a GATA transcription factor and acts in several developmental processes in Drosophila, including embryonic dorsal closure, specification of cardiac cells and bristle determination. We show that pnr is expressed in the mediodorsal parts of thoracic and abdominal segments of embryos, larvae and adult flies. Its activity confers cells with specific adhesion properties that make them immiscible with non-expressing cells. Thus there are two genetic domains in the dorsal region of each segment: a medial (MED) region where pnr is expressed and a lateral (LAT) region where it is not. The homeobox gene iroquois (iro) is expressed in the LAT region. These regions are not formed by separate polyclones of cells, but are defined topographically. We show that ectopic pnr in the wing induces MED thoracic development, indicating that pnr specifies the identity of the MED regions. Correspondingly, when pnr is removed from clones of cells in the MED domain, they sort out and apparently adopt the LAT fate. We propose that (1) the subdivision into MED and LAT regions is a general feature of the Drosophila body plan and (2) pnr is the principal gene responsible for this subdivision. We argue that pnr acts like a classical selector gene but differs in that its expression is not propagated through cell divisions.

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