Fig. 6: Characterization of a Tmem67^ΔCLE/ΔCLE mouse model reveals that loss of TMEM67 cleavage leads to ciliopathy formation in mammals.

a Wt and Tmem67^ΔCLE/ΔCLE littermates at postnatal day 14 (p14) showing impaired growth and a dome-shaped head (red arrowhead) indicative of hydrocephalus formation in Tmem67^ΔCLE/ΔCLE mice (n = 10/10 mice). b Kidneys dissected from Wt and Tmem67^ΔCLE/ΔCLE littermates at p14 showing highly enlarged polycystic kidneys in the mutant mice (n = 10/10 mice). c Hematoxylin and Eosin stained kidney sections from p14 mice show highly cystic renal histopathology in the Tmem67^ΔCLE/ΔCLE mutant kidneys compared to that of a Wt littermate. n = 3 kidneys from each group. d Freeze-fracture scanning electron microscopy (SEM) shows defective primary cilia formation in Tmem67^ΔCLE/ΔCLE kidneys, similar to Tmem67 KO kidneys. The turquoise arrows indicate short cilia, and orange arrows indicate extended primary cilia with abnormal morphologies present on Tmem67 KO and Tmem67^ΔCLE/ΔCLE cystic renal tubular epithelium (n = 3 kidneys from each group). e Transmission electron microscopy (TEM) images of primary cilia showing the transition zone “necklace” (red arrowheads) in a Wt cilium are entirely missing in both types of Tmem67^ΔCLE/ΔCLE primary cilia. The turquoise and orange arrows indicate a short or an extended primary cilium section visualized by TEM (n = 3 kidneys from each group). f SEM images showing highly abnormal, tangled motile cilia with large membrane-bulges (yellow arrowheads) and bulbus-tips present in the ependymal cells lining the lateral brain ventricles in Tmem67^ΔCLE/ΔCLE mice compared to the uniformly organized motile cilia seen in the Wt brain ventricles (n = 3 brains from each group). g TEM images show a similar loss of the TZ necklace formation (red arrowheads) in the Tmem67^ΔCLE/ΔCLE motile ependymal cilia in comparison to Wt (n = 3 brains from each group). Scale bar in (a) is 1 cm, 2 mm in (c), 10 µm in (d), 5 µm or 2 µm in (f), and 200 nm in (e and g).