The UNC-130 signal was first detectable in bean stage embryos (360 min after first cleavage at 22°C) in almost all ventral BWMs; much later than previously reported (Nash et al., 2000). No UNC-130 signal was detected in any dorsal BWM or its precursor during embryogenesis. By the 1.5-fold stage of embryogenesis (460 min) when differentiation is underway, the UNC-130 signal was clearly visible in all ventral BWMs with the exception of one or two left-right pairs located at the anterior end, consistent with
unc-129 expression patterns previously described and discussed below ( Colavita et al., 1998). The anterior half of ventral BWMs consistently had a stronger superGFP signal than their posterior counterparts even though UNC-120 antibody signals were uniform among all BWMs. Confidence that the genome edited superGFP strain reflected endogenous
unc-130 expression came from observations that the ventral BWM pattern completely overlapped (and extended) the BWM pattern obtained using rat polyclonal antibodies raised against the UNC-130 protein, UNC-130::GFP and UNC-130::mCh translational fusion reporter expression patterns, and
unc-130::gfp transcriptional reporter patterns that were all observed predominantly in mid-body, often MS-derived ventral BWMs. Post-embryonically, the signal from the superGFP-edited allele was too faint in BWMs to detect in live animals, mimicking weak antibody staining that was observed in young larvae and early larval signals from the
unc-130::gfp transcriptional reporters.