A defined tubby domain β-barrel surface region of TULP3 mediates ciliary trafficking of diverse cargoes.

The primary cilium is a paradigmatic subcellular compartment at the nexus of numerous cellular and morphogenetic pathways. The tubby family protein TULP3 acts as an adapter of the intraflagellar transport complex A in transporting integral membrane and membrane-associated lipidated proteins into cilia. However, the mechanisms by which TULP3 coordinates ciliary transport of diverse cargoes is not well understood.

Tubb4b is required for multi-ciliogenesis in the mouse.

Cilia are microtubule (MT)-based organelles present on the surface of nearly all vertebrate cells. MTs are polymers of α- and β-tubulins that are each encoded by multiple, individual isotype genes. Tubulin isotype composition is thought to influence MT behaviors.

Interactions between TULP3 tubby domain and ARL13B amphipathic helix promote lipidated protein transport to cilia.

The primary cilium is a nexus for cell signaling and relies on specific protein trafficking for function. The tubby family protein TULP3 transports integral membrane proteins into cilia through interactions with the intraflagellar transport complex-A (IFT-A) and phosphoinositides. It was previously shown that short motifs called ciliary localization sequences (CLSs) are necessary and sufficient for TULP3-dependent ciliary trafficking of transmembrane cargoes.

A dominant tubulin mutation causes cerebellar neurodegeneration in a genetic model of tubulinopathy.

Mutations in tubulins cause distinct neurodevelopmental and degenerative diseases termed "tubulinopathies"; however, little is known about the functional requirements of tubulins or how mutations cause cell-specific pathologies. Here, we identify a mutation in the gene that causes degeneration of cerebellar granule neurons and myelination defects. We show that the neural phenotypes result from a cell type-specific enrichment of a dominant mutant form of relative to the expression other β-tubulin isotypes.

Mutations in Ciliary Trafficking Genes affect Sonic Hedgehog-dependent Neural Tube Patterning Differentially along the Anterior-Posterior Axis.

Cell specification in the ventral spinal cord is a well-studied model system to understand how tissue pattern develops in response to a morphogen gradient. Ventral cell types including motor neurons (MNs) are induced in the neural tube in response to graded Sonic Hedgehog (Shh) signaling. We performed a forward genetic screen in the mouse that incorporated a GFP-expressing transgene to visualize MNs to identify genes regulating ventral patterning.

The Ciliary Protein Arl13b Functions Outside of the Primary Cilium in Shh-Mediated Axon Guidance.

The small GTPase Arl13b is enriched in primary cilia and regulates Sonic hedgehog (Shh) signaling. During neural development, Shh controls patterning and proliferation through a canonical, transcription-dependent pathway that requires the primary cilium. Additionally, Shh controls axon guidance through a non-canonical, transcription-independent pathway whose connection to the primary cilium is unknown.

Cell-Autonomous Hedgehog Signaling Is Not Required for Cyst Formation in Autosomal Dominant Polycystic Kidney Disease.

Background: or , the two main causal genes for autosomal dominant polycystic kidney disease (ADPKD), encode the multipass transmembrane proteins polycystin-1 (PC1) and polycystin-2 (PC2), respectively. Polycystins localize to the primary cilium, an organelle essential for cell signaling, including signal transduction of the Hedgehog pathway. Mutations in ciliary genes that build and maintain the cilium also cause renal cystic disease through unknown pathways.

Tulp3 Is a Ciliary Trafficking Gene that Regulates Polycystic Kidney Disease.

The primary cilium is an organelle essential for cell signaling pathways. One of the most common human genetic diseases is autosomal dominant polycystic kidney disease (ADPKD), which is caused by mutations in the PKD1 or PKD2 genes that encode Polycystin 1 and 2 (PC1/2), transmembrane proteins that translocate to the cilium. Mutations in genes that disrupt ciliogenesis also cause kidney cysts as part of a "ciliopathic" disease spectrum.

Differential timing of granule cell production during cerebellum development underlies generation of the foliation pattern.

Background: The mouse cerebellum (Cb) has a remarkably complex foliated three-dimensional (3D) structure, but a stereotypical cytoarchitecture and local circuitry. Little is known of the cellular behaviors and genes that function during development to determine the foliation pattern. In the anteroposterior axis the mammalian cerebellum is divided by lobules with distinct sizes, and the foliation pattern differs along the mediolateral axis defining a medial vermis and two lateral hemispheres.

A Mathematical Model of Granule Cell Generation During Mouse Cerebellum Development.

Determining the cellular basis of brain growth is an important problem in developmental neurobiology. In the mammalian brain, the cerebellum is particularly amenable to studies of growth because it contains only a few cell types, including the granule cells, which are the most numerous neuronal subtype. Furthermore, in the mouse cerebellum granule cells are generated from granule cell precursors (gcps) in the external granule layer (EGL), from 1 day before birth until about 2 weeks of age.

Clonal analysis reveals granule cell behaviors and compartmentalization that determine the folded morphology of the cerebellum.

The mammalian cerebellum consists of folds of different sizes and shapes that house distinct neural circuits. A crucial factor underlying foliation is the generation of granule cells (gcs), the most numerous neuron type in the brain. We used clonal analysis to uncover global as well as folium size-specific cellular behaviors that underlie cerebellar morphogenesis.

Microdissection and visualization of individual hair follicles for lineage tracing studies.

In vivo lineage tracing is a valuable technique to study cellular behavior. Our lab developed a lineage tracing method, based on the Cre/lox system, to genetically induce clonal labelling of cells and follow their progeny. Here we describe a protocol for temporally controlled clonal labelling and for microdissection of individual mouse hair follicles.

Genetic fate mapping using site-specific recombinases.

Understanding how cells are assembled in three dimensions to generate an organ, or a whole organism, is a pivotal question in developmental biology. Similarly, it is critical to understand how adult stem cells integrate into an existing organ during regeneration or in response to injury. Key to discovering the answers to these questions is being able to study the various behaviors of distinct cell types during development or regeneration.

Hair follicle renewal: authentic morphogenesis that depends on a complex progression of stem cell lineages.

The hair follicle (HF) grows during the anagen phase from precursors in the matrix that give rise to each differentiated HF layer. Little is known about the lineal relationship between these layer-restricted precursors and HF stem cells. To understand how the HF stem cells regenerate the typical anagen organization, we conducted in vivo clonal analysis of key stages of the HF cycle in mice.

Defective planar cell polarity in polycystic kidney disease.

Morphogenesis involves coordinated proliferation, differentiation and spatial distribution of cells. We show that lengthening of renal tubules is associated with mitotic orientation of cells along the tubule axis, demonstrating intrinsic planar cell polarization, and we demonstrate that mitotic orientations are significantly distorted in rodent polycystic kidney models. These results suggest that oriented cell division dictates the maintenance of constant tubule diameter during tubular lengthening and that defects in this process trigger renal tubular enlargement and cyst formation.

Hair follicle renewal: organization of stem cells in the matrix and the role of stereotyped lineages and behaviors.

Hair follicles (HFs) are renewed via multipotent stem cells located in a reservoir (the bulge); however, little is known about how they generate multi-tissue HFs from a proliferative zone (the matrix). To address this issue, we temporally induced clonal labeling during HF growth. Challenging the prevailing hypothesis, we found that the matrix contains restricted self-renewing stem cells for each inner structure.

Methods in clonal analysis and applications.

During development, embryonic cells display a large variety of behaviors that lead to the formation of embryonic structures that are frequently transient. Simultaneously, cells progress towards a specific fate. The current challenge for embryologists is to resolve how these two distinct aspects of development co-exist.

[Antibiotherapy in biliary surgery. Current status].

Without antibiotherapy, biliary surgery is often followed by infectious complications, possibly serious, indeed life-threatening. Biliary bacteria do are responsible of these complications; mainly E. Coli, Streptococcus faecalis (whose pathogenicity is disputed) and Klebsiella.

[Bacteriology of the bile ducts and antibiotic prophylaxis].

The gallbladder wall, gallbladder lumen and bile duct intraoperative sampling materials had been examined in 52 patients with an operation on the biliary tract. All patients were treated by only one infusion before operation: 1 g ceftriaxone was given to 26 patients and 2 g ceftriaxone to the 26 others. Bacterial species were isolated on twenty patients.

[Retroperitoneal and pancreatic mucinous tumors. Immunohistochemical study].

Examples of mucinous tumors from retroperitoneum (2) and pancreas (1) were studied. These tumors share many morphological similarities with ovarian mucinous tumour and adenoma malignum of uterine cervix. They have a similar spectrum of endocrine cells; serotonin, somatostatin, gastrin and pancreatic polypeptide cells were characterized.