Identification and Analysis of Axonemal Dynein Light Chain 1 in Primary Ciliary Dyskinesia Patients

Abstract

Primary ciliary dyskinesia (PCD) is a genetically heterogeneous disorder characterized by chronic infections of the upper and lower airways, randomization of left/right body asymmetry, and reduced fertility. The phenotype results from dysfunction of motile cilia of the respiratory epithelium, at the embryonic node and of sperm flagella. Ultrastructural defects often involve outer dynein arms (ODAs), that are composed of several light (LCs), intermediate, and heavy (HCs) dynein chains. We recently showed that recessive mutations of DNAH5, the human ortholog of the biflagellate Chlamydomonas ODA gamma-HC, cause PCD. In Chlamydomonas, motor protein activity of the gamma-ODA-HC is regulated by binding of the axonemal LC1. We report the identification of the human (DNAL1) and murine (Dnal1) orthologs of the Chlamydomonas LC1-gene. Northern blot and in situ hybridization analyses revealed specific expression in testis, embryonic node, respiratory epithelium, and ependyma, resembling the DNAH5 expression pattern. In silico protein analysis showed complete conservation of the LC1/gamma-HC binding motif in DNAL1. Protein interaction studies demonstrated binding of DNAL1 and DNAH5. Based on these findings, we considered DNAL1 a candidate for PCD and sequenced all exons of DNAL1 in 86 patients. Mutational analysis was negative, excluding a major role of DNAL1 in the pathogenesis of PCD.

Stuck in reverse: loss of LC1 inTrypanosoma bruceidisrupts outer dynein arms and leads to reverse flagellar beat and backward movement

“…1B). Overall, TbLC1 is 46.1% identical to CrLC1, including conservation of all residues proposed to bind ␥HC and p45, the only other protein known to interact with LC1 (Horvath et al, 2005;Sakato and King, 2004). Additionally, both of the basic residues believed to make ionic contact within the ATP-hydrolyzing site of the motor domain are conserved in TbLC1 (Sakato and King, 2004).…”

Standardizing Nasal Nitric Oxide Measurement as a Test for Primary Ciliary Dyskinesia

“…For nNO validation studies at six (non-UNC) sites, PCD was confirmed by PCD-specific ciliary EM defects and, by the presence of biallelic mutations in PCD genes (20)(21)(22)(23)(24)(25)(26)(27)(28)(29)(30)(31). Informed consent was obtained at the University of North Carolina at Chapel Hill and collaborating institutions under the auspices of Committees on the Protection of the Rights of Human Subjects.…”

Primary ciliary dyskinesia associated with normal axoneme ultrastructure is caused byDNAH11mutations

“…In addition, X-linked PCD is occasionally caused by RPGR or OFD1 mutations associated with retinitis pigmentosa or mental retardation, respectively [Vandorp et al, 1992;Zito et al, 2003;Iannaccone et al, 2003;Krawczynski and Witt, 2004;Moore et al, 2006;Budny et al, 2006]. Several other genes have been investigated as candidates for PCD, with negative results [Pennarun et al, 2000[Pennarun et al, , 2002Maiti et al, 2000;Bartoloni et al, 2001;Neesen et al, 2002;Zariwala et al, 2004;Horvath et al, 2005]. A homozygous mutation in the dynein HC DNAH11 (MIM] 603339) has recently been associated with situs inversus and immotile respiratory cilia that have a normal axonemal ultrastructure [Bartoloni et al, 2002].…”