However, the Q49X mutant failed to display detectable gap-junction plaques in N2A cells (Fig. 2B) and the junctional current (Ij) at 20 mV transjunctional voltage gradient (Vj, Fig. 2C) was absent, indicating that the mutant failed to reach cell-cell interfaces and was therefore unable to form functional gap-junction channels.
The role of Bar1 in mediating cell membrane organization was confirmed as ΔBAR1 mutants failed to display a distinct sterol-rich domain at the hyphal tip.
Despite evidence that NRPD1 and NRPE1/NRPD1b active site mutants are expressed at the same levels as non-mutant recombinant proteins and are not impaired in their ability to assemble with the NRPD2 subunit, the active site mutants fail to display the characteristic punctate nucleoplasmic localization patterns typical of wild-type NRPD1 or NRPE1.
Under Light/Dark (LD) cycles consisting of 12 h of light and 12 h of darkness (LD 12∶12), Pdf01 mutants fail to display the normal anticipation of the morning lights-on transition and have a significantly advanced evening peak of activity, which results in an increase in daytime activity [17].
If a small number of gene family members are implicated in redundancy and single mutants fail to display a genotype, researchers can use predictions to guide the construction of double or higher mutants.
Finally, the Nrp1 VEGF− mutants failed to display the perinatal lethality or cardiac defect observed in the Nrp1 Sema− mutants (Gu et al., 2003), further confirming functional SEMA3-NRP1 bindiNrp1n Nrp1 VEGF− mice.
MyoD-null mutant mice failed to display any major shift in MyHC expression, although subtle shifts in the fibre type of fast muscles towards a slower character were seen; in slow muscle a tendency towards a faster phenotype was observed (Hughes et al., 1997; Seward et al., 2001).
The FM4-64 staining revealed that endocytosis was blocked by disruption of MoVAM7, and the ΔMovam7 mutants also failed to display the presence of the Spitzenkörper body, the structure associated with fast growing hyphal tips in filamentous fungi.
Compared with wild-type siblings that showed outpocketing of a new pouch every 4 h (Fig. 1A-G; supplementary material Movie 1A), her5:mCherryCAAX-positive endodermal cells were present in tbx1 mutants yet failed to display outpocketing behavior within the 10-h timeframe of the recordings (Fig. 1H-K; supplementary material Movie 1B).
If the TRKB point mutants analyzed in this study indeed fail to display gain-of-function transforming properties, this would suggest that they represent passenger mutations and did not drive tumor formation.
In agreement with this prediction, we found that transheterozygous mutant neurons (ena−/+ chic−/+), which showed modest, though significant reductions in Chic and Ena levels (Fig. 4L), failed to display any filopodial length phenotypes (Fig. 4E).
