Mouse mutagenesis identifies novel roles for left–right patterning genes in pulmonary, craniofacial, ocular, and limb development

Abstract

Vertebrate organs show consistent left-right (L-R) asymmetry in placement and patterning. To identify genes involved in this process we performed an ENU-based genetic screen. Of 135 lines analyzed 11 showed clear single gene defects affecting L-R patterning, including 3 new alleles of known L-R genes and mutants in novel L-R loci. We identified six lines (termed "gasping") that, in addition to abnormal L-R patterning and associated cardiovascular defects, had complex phenotypes including pulmonary agenesis, exencephaly, polydactyly, ocular and craniofacial malformations. These complex abnormalities are present in certain human disease syndromes (e.g., HYLS, SRPS, VACTERL). Gasping embryos also show defects in ciliogenesis, suggesting a role for cilia in these human congenital malformation syndromes. Our results indicate that genes controlling ciliogenesis and left-right asymmetry have, in addition to their known roles in cardiac patterning, major and unexpected roles in pulmonary, craniofacial, ocular and limb development with implications for human congenital malformation syndromes. Developmental Dynamics 238:581-594, 2009.

Static respiratory cilia associated with mutations in Dnahc11/DNAH11: A mouse model of PCD

“…Mean tracheal CBF was 18.9 Hz (SEM = 0.21 Hz, n = 12) in wild-type mice while cilia were static in samples from the mutant cohort (n = 12) with the exception of occasional slow ciliary movement in one individual. The specificity of this defect was confirmed by analyzing the Dnahc11 lrm3 (lrm3) mutant, a presumed null allele; lrm3 lacks 50 amino acids from the hinge region and phenocopies the iv situs phenotype [Ermakov et al, 2009]. lrm3 homozgotes (n = 6) showed no ciliary beat in five individuals with one mean value of 18.6 Hz (Fig.…”

“…However, the basis of the immotile cilia in patient #616 remains difficult to ascertain as only a single truncated allele has so far been identified. In contrast, the iv and lrm3 mouse lines show immotile tracheal cilia from presumed null mutations [Ermakov et al, 2009;Supp et al, 1999] arguing that the true null phenotype is immotile cilia. Further study will be required to determine whether mouse and human cilia truly have identical requirements for DNAH11/Dnahc11 function.…”

“…Congenic iv/+ mice were derived by 10 generations of backcrosses to C3H/HeH (C3H); C3H-congenic experimental cohorts were from congenic iv/+ intercrosses. C3H/HeH congenic Dnahc11 lrm3 (lrm3) are as previously described [Ermakov et al, 2009]. SNP genotyping was for the published mutations [Ermakov et al, 2009;Supp et al, 1997].…”

“…C3H/HeH congenic Dnahc11 lrm3 (lrm3) are as previously described [Ermakov et al, 2009]. SNP genotyping was for the published mutations [Ermakov et al, 2009;Supp et al, 1997]. Samples were collected postmortem, following terminal anaesthesia using sodium pentobarbitone (Euthatal).…”

“…Subsequently, in a morphology-based study, tracheal cilia and sperm were reported to demonstrate normal motility [Handel and Kennedy, 1984]. Other alleles include an engineered null allele Dnahc11 tm1Ssp [Supp et al, 1999] and a splicing mutant Dnahc11 lrm3 (lrm3) that lacks 50 amino acids from the hinge region [Ermakov et al, 2009] both similarly demonstrate L-R defects, although nodal cilia motility has not been assayed in these alleles.…”