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Complementary Patterns (complementary + pattern)

Distribution by Scientific Domains

Life Sciences	100%

Selected Abstracts

Early and transient ontogenetic expression of the cocaine- and amphetamine-regulated transcript peptide in the rat mesencephalon: Correlation with tyrosine hydroxylase expression

DEVELOPMENTAL NEUROBIOLOGY, Issue 3 2002
F. Brischoux
Abstract The ontogeny of cocaine- and amphetamine-regulated transcript (CART) expression has been analyzed by immunohistochemistry in the mesencephalon of the rat central nervous system, and compared to the pattern of tyrosine hydroxylase- (TH-) expression. CART-producing neurons were first detected on the embryonic day 11 (E11) in the ventral mesencephalic vesicle. These neurons are among the first cells of the mantle layer to differentiate. From E13, a complementary pattern of distribution was observed, dividing the mantle layer into an external TH zone and an internal CART zone. Many TH-positive neurons were found to migrate from the neuroepithelium through the area containing the CART-immunoreactive neurons to settle more laterally. These TH cells exhibited prominent leading and trailing dendrites in the immediate vicinity of CART perikarya. On E16, the number of CART neurons appeared to diminish, and they were confined near the ventricle and around the fasciculus retroflexus. On E18 and E20, only the Edinger-Westphal nucleus exhibited a strong CART staining as described in the adult brain. Thus, the very early detection of CART during prenatal ontogeny led us to speculate that this peptide might have a role in the development of specific regions of the rat brain. In particular, our observations suggest that CART-expressing neurons might help the migration of the dopaminergic neurons of the substantia nigra. © 2002 Wiley Periodicals, Inc. J Neurobiol 52: 221,229, 2002 [source]

Complementary expression and heterophilic interactions between igLON family members neurotrimin and LAMP

DEVELOPMENTAL NEUROBIOLOGY, Issue 3 2002
Orlando D. Gil
Abstract Neurotrimin (Ntm) and the limbic system-associated membrane protein (LAMP) are members of the IgLON (LAMP, OBCAM, Ntm) family of glycorylphosphatidylinositol anchored neural cell adhesion molecules. We previously reported that LAMP and Ntm promote adhesion and neurite outgrowth via a homophilic mechanism, suggesting that these proteins promote the formation of specific neuronal circuits by homophilic interactions. In this report, we have further characterized the expression and binding specificity of Ntm. Using a newly generated monoclonal antibody to Ntm, we demonstrated that this protein is largely expressed in a complementary pattern to that of LAMP in the nervous system, with co-expression at a few sites. Ntm is expressed at high levels in sensory-motor cortex and, of particular note, is transiently expressed in neurons of cortical barrel fields and corresponding thalamic "barreloids." Binding of a recombinant, soluble form of Ntm to CHO cells expressing either Ntm or LAMP demonstrates that Ntm and LAMP interact both homophilically and heterophilically. In contrast to conventional growth-promoting activity of Ig superfamily members, LAMP strongly inhibits the outgrowth of Ntm-expressing dorsal root ganglion (DRG) neurons in a heterophilic manner. These anatomical and functional data support the concept that homophilic and heterophilic interactions between IgLON family members are likely to play a role in the specification of neuronal projections via growth promoting and inhibiting effects, respectively. © 2002 Wiley Periodicals, Inc. J Neurobiol 51: 190,204, 2002 [source]

Role for retinoid signaling in left,right asymmetric digestive organ morphogenesis

DEVELOPMENTAL DYNAMICS, Issue 8 2006
Kristen Lipscomb
Abstract The looping events that establish left,right asymmetries in the vertebrate gut tube are poorly understood. Retinoic acid signaling is known to impact left,right development in multiple embryonic contexts, although its role in asymmetric digestive organ morphogenesis is unknown. Here, we show that the genes for retinaldehyde dehydrogenase (RALDH2) and a retinoic acid hydroxylase (CYP26A1) are expressed in complementary patterns in the Xenopus gut during looping. A late-stage chemical genetic assessment reveals that agonists and antagonists of retinoid signaling generate abnormal gut looping topologies, digestive organ heterotaxias, and intestinal malrotations. Accessory organ deformities commonly associated with intestinal malrotation in humans, such as annular pancreas, pancreas divisum, and extrahepatic biliary tree malformations, are also induced by distinct retinoid receptor agonists. Thus, late-stage retinoic acid signaling is likely to play a critical role in asymmetric gut tube morphogenesis and may underlie the etiology of several clinically relevant defects in the digestive system. Developmental Dynamics 235:2266,2275, 2006. © 2006 Wiley-Liss, Inc. [source]

Indirect effects of algae on coral: algae-mediated, microbe-induced coral mortality

ECOLOGY LETTERS, Issue 7 2006
Jennifer E. Smith
Abstract Declines in coral cover are generally associated with increases in the abundance of fleshy algae. In many cases, it remains unclear whether algae are responsible, directly or indirectly, for coral death or whether they simply settle on dead coral surfaces. Here, we show that algae can indirectly cause coral mortality by enhancing microbial activity via the release of dissolved compounds. When coral and algae were placed in chambers together but separated by a 0.02 ,m filter, corals suffered 100% mortality. With the addition of the broad-spectrum antibiotic ampicillin, mortality was completely prevented. Physiological measurements showed complementary patterns of increasing coral stress with proximity to algae. Our results suggest that as human impacts increase and algae become more abundant on reefs a positive feedback loop may be created whereby compounds released by algae enhance microbial activity on live coral surfaces causing mortality of corals and further algal growth. [source]

Class III HD-Zip gene regulation, the golden fleece of ARGONAUTE activity?

BIOESSAYS, Issue 9 2004
John L. Bowman
MicroRNAs, small noncoding RNAs, are implicated in gene regulation in both metazoans and plants. In plants, many of the targets of miRNA-mediated gene regulation encode transcription factors with functions in development, such as the Class III HD-Zip gene family whose members direct polarity establishment in leaves and vasculature. Three recent papers provide insight into how miRNAs, likely acting through a complex containing an Argonaute protein, regulate Class III HD-Zip gene expression in Arabidopsis and maize.1,3 While the precise biological activity of Argonaute proteins remains an enigma, ARGONAUTE1 in Arabidopsis is required for the proper regulation of miRNA165/166, which targets cleavage of Class III HD-Zip mRNAs. Consistent with their proposed role in negative regulation, expression of miRNA165/166 is complementary to that of Class III HD-Zip gene expression, but this is perturbed in agronaute1 mutants. Determining how these complementary patterns of expression are formed should lead us closer to an understanding of the molecular mechanisms by which asymmetry is established in developing leaves. BioEssays 26:938,942, 2004. © 2004 Wiley Periodicals, Inc. [source]