Genome sequencing of balancer strains reveals previously unappreciated complex genomic rearrangements.

Genetic balancers in are complex variants that allow lethal or sterile mutations to be stably maintained in a heterozygous state by suppressing crossover events. Balancers constitute an invaluable tool in the scientific community and have been widely used for decades. The first/traditional balancers were created by applying X-rays, UV, or gamma radiation on strains, generating random genomic rearrangements.

Whole genome sequencing facilitates intragenic variant interpretation following modifier screening in C. elegans.

Background: Intragenic modifiers (in-phase, second-site variants) are known to have dramatic effects on clinical outcomes, affecting disease attributes such as severity or age of onset. However, despite their clinical importance, the focus of many genetic screens in model systems is on the discovery of extragenic variants, with many labs still relying upon more traditional methods to identify modifiers. However, traditional methods such as PCR and Sanger sequencing can be time-intensive and do not permit a thorough understanding of the intragenic modifier effects in the context of non-isogenic genomic backgrounds.

Deciphering complex genome rearrangements in C. elegans using short-read whole genome sequencing.

Genomic rearrangements cause congenital disorders, cancer, and complex diseases in human. Yet, they are still understudied in rare diseases because their detection is challenging, despite the advent of whole genome sequencing (WGS) technologies. Short-read (srWGS) and long-read WGS approaches are regularly compared, and the latter is commonly recommended in studies focusing on genomic rearrangements.

The Axenfeld-Rieger Syndrome Gene Contributes to Left-Right Patterning.

Precise spatiotemporal expression of the -- cascade in the lateral plate mesoderm establishes the left-right axis, which provides vital cues for correct organ formation and function. Mutations of one cascade constituent and, separately, the Forkhead transcription factor independently cause a multi-system disorder known as Axenfeld-Rieger syndrome (ARS). Since cardiac involvement is an established ARS phenotype and because disrupted left-right patterning can cause congenital heart defects, we investigated in zebrafish whether contributes to organ laterality or situs.

Dissecting the Genetic and Etiological Causes of Primary Microcephaly.

Autosomal recessive primary microcephaly (MCPH; "small head syndrome") is a rare, heterogeneous disease arising from the decreased production of neurons during brain development. As of August 2020, the Online Mendelian Inheritance in Man (OMIM) database lists 25 genes (involved in molecular processes such as centriole biogenesis, microtubule dynamics, spindle positioning, DNA repair, transcriptional regulation, Wnt signaling, and cell cycle checkpoints) that are implicated in causing MCPH. Many of these 25 genes were only discovered in the last 10 years following advances in exome and genome sequencing that have improved our ability to identify disease-causing variants.

Evolution and expression of the zebrafish unc119 paralogues indicates a conserved role in cilia.

UNC119 proteins are required for ciliary trafficking in a process called lipidated protein intraflagellar targeting (LIFT) or through vesicle transport. However, although unc119 has been studied in a variety of contexts, either organismal constraints or genetic redundancy has largely restricted their study in ciliary contexts. One possible solution for this is to use the zebrafish, however, the unc119 genes have not been well described in this species.

Coordinating the uncoordinated: UNC119 trafficking in cilia.

Constructing the distinct subcellular environment of the cilium relies in a large part upon intraflagellar transport (IFT) proteins, which traffic cargo both to and within the cilium. However, evidence from the last 10 years suggests that IFT alone is not sufficient to generate the ciliary environment. One essential factor is UNC119, which interacts with known IFT molecular switches to transport ciliary cargos.

Unc45b is essential for early myofibrillogenesis and costamere formation in zebrafish.

Despite the prevalence of developmental myopathies resulting from muscle fiber defects, the earliest stages of myogenesis remain poorly understood. Unc45b is a molecular chaperone that mediates the folding of thick-filament myosin during sarcomere formation; however, Unc45b may also mediate specific functions of non-muscle myosins (NMMs). unc45b Mutants have specific defects in striated muscle development, which include myocyte detachment indicative of dysfunctional adhesion complex formation.

The myosin chaperone UNC45B is involved in lens development and autosomal dominant juvenile cataract.

Genome-wide linkage analysis, followed by targeted deep sequencing, in a Danish multigeneration family with juvenile cataract revealed a region of chromosome 17 co-segregating with the disease trait. Affected individuals were heterozygous for two potentially protein-disrupting alleles in this region, in ACACA and UNC45B. As alterations of the UNC45B protein have been shown to affect eye development in model organisms, effort was focused on the heterozygous UNC45B missense mutation.