C. elegans PAT-9 is a nuclear zinc finger protein critical for the assembly of muscle attachments

Abstract

BackgroundCaenorhabditis elegans sarcomeres have been studied extensively utilizing both forward and reverse genetic techniques to provide insight into muscle development and the mechanisms behind muscle contraction. A previous genetic screen investigating early muscle development produced 13 independent mutant genes exhibiting a Pat (paralyzed and arrested elongation at the two-fold length of embryonic development) muscle phenotype. This study reports the identification and characterization of one of those genes, pat-9.ResultsPositional cloning, reverse genetics, and plasmid rescue experiments were used to identify the predicted C. elegans gene T27B1.2 (recently named ztf-19) as the pat-9 gene. Analysis of pat-9 showed it is expressed early in development and within body wall muscle lineages, consistent with a role in muscle development and producing a Pat phenotype. However, unlike most of the other known Pat gene family members, which encode structural components of muscle attachment sites, PAT-9 is an exclusively nuclear protein. Analysis of the predicted PAT-9 amino acid sequence identified one putative nuclear localization domain and three C2H2 zinc finger domains. Both immunocytochemistry and PAT-9::GFP fusion expression confirm that PAT-9 is primarily a nuclear protein and chromatin immunoprecipitation (ChIP) experiments showed that PAT-9 is present on certain gene promoters.ConclusionsWe have shown that the T27B1.2 gene is pat-9. Considering the Pat-9 mutant phenotype shows severely disrupted muscle attachment sites despite PAT-9 being a nuclear zinc finger protein and not a structural component of muscle attachment sites, we propose that PAT-9 likely functions in the regulation of gene expression for some necessary structural or regulatory component(s) of the muscle attachment sites.

Mapping and analysis of Caenorhabditis elegans transcription factor sequence specificities

“…We obtained dozens of significant relationships ( Figure 9 ), including known roles for GATA TFs in the regulation of intestinal gene expression (and related GO categories) ( Pauli et al, 2006 ; McGhee, 2007 ), HLH-1 in the regulation of muscle gene expression ( Fukushige et al, 2006 ), DAF-19 (an RFX TF) in the regulation of ciliary genes ( Swoboda et al, 2000 ), and PHA-4 in development of the pharynx ( Gaudet and Mango, 2002 ) (boxed in Figure 9 ). We also note that the association of the motif for ZTF-19 (PAT-9), a C2H2 ZF protein, with genes expressed in L2 body wall muscle tissue is consistent with observed expression patterns for this gene in body wall muscle, as well as defective muscle development in a mutant ( Liu et al, 2012 ). The ZTF-19 binding motif may, therefore, enable the identification of specific downstream targets.…”

SRGP-1/srGAP and AFD-1/Afadin stabilize HMP-1/α-Catenin at rosettes to seal internalization sites following gastrulation inC. elegans

“…One such modulator in vertebrates is vinculin; when the αE-catenin M domain is extended, either via direct mechanical distension [58–60] or by introducing salt bridge mutations [51], its binding affinity for vinculin is increased. However, DEB-1, the vinculin homolog in C. elegans does not interact with HMP-1 [47], and its expression is confined to muscle cells during development [61–63], ruling it out as a candidate HMP-1 interactor that could be positively affected by the R551/554A salt bridge mutations in the context of cleft closure. Another candidate modulator is AFD-1/afadin.…”

Molecular Effects of Silver Nanoparticles on Monogenean Parasites: Lessons from Caenorhabditis elegans

“…In C. elegans , ifb-1 performs an important role in the transmission of muscle force to the cuticle and to the maintenance of the correct hypodermis/muscle relationship; lack of ifb-1 gene causes morphological defects and defective excretory cells [ 96 ]. At the same time, parasites exposed to the higher concentration of AgNPs showed up-regulation of genes acting in body wall muscle attachments, such as pat-6 /actopaxin [ 69 , 101 ] and ajm-1 (apical junction component 1) located on the apical junctional domain of the basal epithelia of C. elegans to the HMR–HMP (cadherin–catenin) complex, which is important for the structural maintenance of the epithelium [ 71 , 102 ], and lon-3 , secreted by the hypodermis and required for body size regulation [ 88 , 103 ]. At both AgNP concentrations, the gene cuticlin-1 ( cut-1 ) was down-regulated; this gene encodes a non-collagenous component of C. elegans cuticle that contributes to the formation of extracellular envelopes protecting the organism from the environment [ 104 ].…”