Le site de vulgarisation scientifique de l’Université de Liège. ULg, Université de Liège

The genetics of fluttering cilia
3/17/11

The vibrant cilia, a complex cog in the machinery

‘One in two patients has a situs inversus, in other words a reversal in a mirror position of organs in relationship to the normal position. That is connected to the role played by the cilia in establishing organ symmetry over embryo development. When we see a situs inversus in someone, it’s a sign and we think of PCD straightaway,’ points out the scientist. Subsequently – or for patients which do not have a situs inversus but instead present frequent respiratory infections – a biopsy allow a diagnosis to be made/confirmed. The analysis of these ciliary cells by electronic microscope and the placing of these cells in a culture reveals if their functioning and/or structure has anomalies. For, if the movement of these cilia is not optimal in the case of a PCD, that flows from modifications which appear in their structure.

But what is a vibrant cilia made of? Briefly, a cilia is made up of nine peripheral pairs and one central pair of microtubules. Each doublet of peripheral microtubules is equipped with external and inner dynein arms, a complex protein also called a ‘movement protein’ (see the diagram). ‘For the cilia to flutter there has to be slippage between these microtubules, which is orchestrated by the dynein,’ explain the researchers. The dynein arms can in effect hang on to the preceding microtubule and thus ‘bend’ the cilia.

‘The vibrant cilia are complex structures which contain numerous components. The defects we can observe within the structure of the cilia arise from the mutation of several genes,’ adds Michel Georges.

TEM FR

 

When the bobtail lends its genome

The study of PCD in humans is complex as it does not concern a disease with a single origin, and several genes are responsible for its development. ‘It is what we call a heterogeneous disease,’ states Michel Georges. ‘The families of patients in which PCD appears have mutations in different genes. That makes studying this disease more difficult as each family is unique,’ he continues.

 

Page : previous 1 2 3 next

 


© 2007 ULi�ge