Dwarfism Research Today is a free monthly online journal that collates and summarizes the latest research about Dwarfism, including details on genetics, diet, mental and motor development.

The Centrosomal Protein Pericentrin Identified at the Basal Body Complex of the Connecting Cilium in Mouse Photoreceptors.

Mühlhans J, Brandstätter JH, Gießl A

Department of Biology, Animal Physiology, University of Erlangen-Nuremberg, Erlangen, Germany.

BACKGROUND: Pericentrin (Pcnt), a conserved protein of the pericentriolar material, serves as a multifunctional scaffold for numerous proteins and plays an important role in microtubule organization. Recent studies indicate that Pcnt mutations are associated with a range of diseases including primordial dwarfism and ciliopathies. To date, three Pcnt splice variants from orthologous genes in mice and humans are known. PRINCIPAL FINDINGS: We generated a specific Pcnt antiserum detecting all known Pcnt splice variants and examined the cellular and subcellular distribution of Pcnt in ciliated tissues of the mouse, the olfactory epithelium and the retina. For the first time, we identified Pcnt and its centrosomal interaction partners at the basal body complex of mouse retinal photoreceptors. Photoreceptors are morphologically and functionally subdivided into the light sensitive outer segment and the inner segment comprising the metabolic function of the cell. The two compartments are linked via a modified, specialized, non-motile cilium, the connecting cilium. Here, Pcnt colocalized with the whole protein machinery responsible for transport processes between the two compartments. Surprisingly, photoreceptors expressed a small Pcnt splice transcript - most likely a modified variant of Pcnt S - which was not present in receptor neurons of the olfactory epithelium. CONCLUSIONS: Our findings suggest distinct functional roles of several Pcnt variants in different ciliated tissues and sensory neurons, like the olfactory epithelium and the retina of the mouse. The individual patchwork of different Pcnt splice transcripts seems to reflect the complexity of Pcnt function, an assumption corroborated by the heterogeneous clinical manifestations associated with mutations in the Pcnt gene.

Published 27 October 2011 in PLoS One, 6(10): e26496.
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Articles on Dwarfism published 25 October 2011:

Nonsense-mediated mRNA decay factors, UPF1 and UPF3, contribute to plant defense.   Plant Cell Physiol.

In Arabidopsis, the NMD-defective mutants, upf1-5 and upf3-1 are characterized by dwarfism, curly leaves and late flowering. These phenotypes are similar to those of mutants showing constitutive PR gene expression, SA accumulation and, subsequently, resistance to pathogens. The disease symptoms of upf1-5 and upf3-1 mutants were observed following infection with the virulent pathogen Pst DC3000 with the aim of determining whether the loss of NMD is involved in disease resistance. These mutant ... [Abstract] [Full-text]

Articles on Dwarfism published 24 October 2011:

A homozygous mutation in RNU4ATAC as a cause of microcephalic osteodysplastic primordial dwarfism type I (MOPD I) with associated pigmentary disorder.   Am J Med Genet A, 155(11): 2885-96.

The designation microcephalic osteodysplastic primordial dwarfism (MOPD) refers to a group of autosomal recessive disorders, comprising microcephaly, growth retardation, and a skeletal dysplasia. The different types of MOPD have been delineated on the basis of clinical, radiological, and genetic criteria. We describe two brothers, born to healthy, consanguineous parents, with intrauterine and postnatal growth retardation, microcephaly with abnormal gyral pattern and partial agenesis of corpus ... [Abstract] [Full-text]

Insertional mutation in the Golgb1 gene is associated with osteochondrodysplasia and systemic edema in the OCD rat.   Bone, 49(5): 1027-36.

Homozygous rats (ocd/ocd) of a mutant inbred strain, OCD (osteochondrodysplasia), show osteochondrodysplasia, systemic edema, cleft palate, protruding tongue, disproportionate dwarfism, and lethality immediately after birth. Their epiphyses show decreased levels of glycosaminoglycans and weak staining for extracellular matrix proteins. The epiphyseal chondrocytes have large vesicles and expanded endoplasmic reticulum and Golgi apparatus. These phenotypic features are inherited in an autosomal ... [Abstract] [Full-text]

Articles on Dwarfism published 20 October 2011:

Molecular characterisation of Rht-1 dwarfing genes in hexaploid wheat (Triticum aestivum).   Plant Physiol.

The introduction of the Rht-B1b and Rht-D1b semi-dwarfing genes led to impressive increases in wheat yields during the 'Green Revolution'. The reduction in stem elongation in varieties containing these alleles is caused by a limited response to the phytohormone, gibberellin (GA), resulting in improved resistance to stem lodging and yield benefits through an increase in grain number. Rht-B1 and Rht-D1 encode DELLA proteins, which act to repress GA-responsive growth, and their mutant alleles ... [Abstract] [Full-text]

Articles on Dwarfism published 19 October 2011:

Dominant and pleiotropic effects of a GAI gene in wheat results from lack of interaction between DELLA and GID1.   Plant Physiol.

Dominance, semidominance and recessiveness are important modes of Mendelian inheritance. The phytohormone gibberellin (GA) regulates many plant growths and developmental processes. The previously cloned semidominant GAI (GA-insensitive) genes Rht1 and Rht2 in wheat were the basis of the 'green revolution'. However, no completely dominant GAI gene has been cloned. Here, we report molecular characterization of Rht-B1c, a dominant GAI allele in wheat, which confers more extreme characteristics ... [Abstract] [Full-text]

Inducible nitric oxide synthase-nitric oxide signaling mediates the mitogenic activity of Rac1 during endochondral bone growth.   J Cell Sci, 124: 3405-13.

Coordinated proliferation and differentiation of growth plate chondrocytes controls endochondral bone growth and final height in humans, and disruption of this process results in diseases of the growing and adult skeleton, such as chondrodysplasias or osteoarthritis. We had shown recently that chondrocyte-specific deletion of the gene Rac1 in mice leads to severe dwarfism due to reduced chondrocyte proliferation, but the molecular pathways involved remained unclear. Here, we demonstrate that ... [Abstract] [Full-text]

Anaesthetic management of a parturient with Laron syndrome.   Int J Obstet Anesth, 20(4): 344-6.

We report a case of a parturient with Laron syndrome, a rare form of dwarfism which results from an inability to generate insulin-like growth factor 1. In addition to dwarfism these patients may have craniofacial abnormalities, atlantoaxial instability, spinal stenosis and metabolic, musculoskeletal and genitourinary abnormalities. The patient underwent an urgent caesarean section using combined spinal-epidural anaesthesia. Laron syndrome is reviewed and its anaesthetic implications discussed. [Abstract] [Full-text]

Sulfate in fetal development.   Semin Cell Dev Biol, 22(6): 653-9.

Sulfate (SO(4)(2-)) is an important nutrient for human growth and development, and is obtained from the diet and the intra-cellular metabolism of sulfur-containing amino acids, including methionine and cysteine. During pregnancy, fetal tissues have a limited capacity to produce sulfate, and rely on sulfate obtained from the maternal circulation. Sulfate enters and exits placental and fetal cells via transporters on the plasma membrane, which maintain a sufficient intracellular supply of sulfate ... [Abstract] [Full-text]

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