Rotatin and its homologues such as Ana3 in Drosophila are found to be essential for centriole function. A deficiency of rotatin in mice leads to randomised heart tube looping, defects in embryonic turning, and abnormal expression of HNF3beta, lefty, and nodal. Thus it is required for left-right and axial patterning. Ana3 - the Drosophila homologue - is present in centrioles and basal bodies, is required for the structural integrity of both centrioles and basal bodies and for centriole cohesion. Rotatin also localises to centrioles and basal bodies and appears to be essential for cilia function. This entry represents the N-terminal domain.