The dynamic cilium in human diseases

Cilia are specialized organelles protruding from the cell surface of almost all mammalian cells. They consist of a basal body, composed of two centrioles, and a protruding body, named the axoneme. Although the basic structure of all cilia is the same, numerous differences emerge in different cell types, suggesting diverse functions. In recent years many studies have elucidated the function of 9+0 primary cilia. The primary cilium acts as an antenna for the cell, and several important pathways such as Hedgehog, Wnt and planar cell polarity (PCP) are transduced through it. Many studies on animal models have revealed that during embryogenesis the primary cilium has an essential role in defining the correct patterning of the body. Cilia are composed of hundreds of proteins and the impairment or dysfunction of one protein alone can cause complete loss of cilia or the formation of abnormal cilia. Mutations in ciliary proteins cause ciliopathies which can affect many organs at different levels of severity and are characterized by a wide spectrum of phenotypes. Ciliary proteins can be mutated in more than one ciliopathy, suggesting an interaction between proteins. To date, little is known about the role of primary cilia in adult life and it is tempting to speculate about their role in the maintenance of adult organs. The state of the art in primary cilia studies reveals a very intricate role. Analysis of cilia-related pathways and of the different clinical phenotypes of ciliopathies helps to shed light on the function of these sophisticated organelles. The aim of this review is to evaluate the recent advances in cilia function and the molecular mechanisms at the basis of their activity

Sovereign ratings and oil-exporting countries: the effect of high oil prices on ratings

We investigate how high and rising oil prices in the 2003-2008 period affected the sovereign ratings of oil-exporting countries, after controlling for fundamentals. Based on a large dataset of countries from Standard and Poor's and Moody's, we find strong statistical evidence of a large ratings premium - nearly two notches - for those oil-exporting countries with a large share of net oil revenue to gross domestic product, relative to countries with similar economic fundamentals. We have some limited forecast information from the rating agencies and the effect increases when we include this information, providing further evidence that this ratings premium is not driven by expected improvements in fundamentals. This finding has implications for asset prices in oil-exporting countries and highlights the risk that in the event of a sharp unanticipated drop in oil prices, sovereign rating downgrades of oil-exporting countries could be sharper than the deterioration in their economic fundamentals