The hydrocephalus inducing gene product, Hydin, positions axonemal central pair microtubules.
BACKGROUND
Impairment of cilia and flagella function underlies a growing number of human genetic diseases. Mutations in hydin in hy3 mice cause lethal communicating hydrocephalus with early onset. Hydin was recently identified as an axonemal protein; however, its function is as yet unknown.


RESULTS
Here we use RNAi in Trypanosoma brucei to address this issue and demonstrate that loss of Hydin causes slow growth and a loss of cell motility. We show that two separate defects in newly-formed flagellar central pair microtubules underlie the loss of cell motility. At early time-points after RNAi induction, the central pair becomes mispositioned, while at later time points the central pair is lost. While the basal body is unaffected, both defects originate at the basal plate, reflecting a role for TbHydin throughout the length of the central pair.


CONCLUSIONS
Our data provide the first evidence of Hydin's role within the trypanosome axoneme, and reveal central pair anomalies and thus impairment of ependymal ciliary motility as the likely cause of the hydrocephalus observed in the hy3 mouse.
Dawe
Helen R
HR
Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford, OX1 3RE, UK. helen.dawe@path.ox.ac.uk
Shaw
Michael K
MK
Farr
Helen
H
Gull
Keith
K
D000818:Animals; D001483:Base Sequence; D017931:DNA Primers; D006849:Hydrocephalus / Q000235:genetics*; D051379:Mice; D008840:Microfilament Proteins / Q000235:genetics*; D008870:Microtubules; D015800:Protozoan Proteins / Q000502:physiology*; D034622:RNA Interference; D014346:Trypanosoma brucei brucei / Q000235:genetics*
D017931:DNA Primers; C481382:Hydin protein, mouse; D008840:Microfilament Proteins; D015800:Protozoan Proteins