Dynein Chains Affected by the Absence of TTC12 and Diagrammatic Representation of the Axonemal Components Impacted by TTC12 Loss-of-Function Mutations in Respiratory Cilia and Sperm Flagella
(A) Table summarizing the dynein chains studied by IF in AECs of a control and of individuals 18GM00157, DCP1606, DCP153, in AEC cultures invalidated or not for TTC12 by a CRISPR-Cas9 approach, and in spermatozoa from a control and from individual DCP153. ODA labeling was performed with anti-DNAH5 and anti-DNAH9 antibodies in AECs and anti-DNAH8 and anti-DNAH17 antibodies in spermatozoa. Black check marks represent normal localization, minus signs represent an absence of protein, and black cross signs indicate mislocalization. NR: not relevant.
(B) Schematic structure of a normal 96-nm-long axonemal unit. Each unit, which repeats along the microtubule doublets, consists of four ODAs represented in purple and IDAs shown in blue. Because the exact composition of IDAs is virtually unknown in humans, the IDA representation is based on data from Chlamydomonas, in which the seven IDA subspecies include six single-headed DAs (a, b, c, e, g, and d) and one double-headed DA (IDA-I1).
(C) Phenotype of TTC12-deficient respiratory cilia versus TTC12-deficient sperm flagella. The proteins unaffected by the loss of TTC12 are represented in full color and written in yellow, and the proteins affected by the loss of TTC12 are represented in white with a red dotted line and written in red. The proteins found to be affected by TTC12 mutations, but for which the exact localization is unknown in humans, are represented in a hatched red pattern and are written in red. Proteins with lower but non-null expression are represented in a hatched gray pattern and are written in red. The proteins that could not be tested are represented and written in gray.
Abbreviations are as follows: ODA, outer dynein arm; IDA, inner dynein arm; N-DRC, nexin-dynein regulatory complex; MIA, modifier of inner arms; IC/LC, intermediate chain/light chain, RS, radial spoke; and MT, microtubules.