Mutant/mutation
The mutant expresses a C-terminal GFP-tagged version of IMC1b (inner membrane complex protein 1b).

Protein (function)
The imcb1b gene belongs to small 'family' of conserved genes that express putative membrane skeleton proteins which contain domains that share sequence homology to domains of articulins, proteins of membrane skeleton of free-living protists and show homology to the inner membrane complex protein 1 (TgIMC1) of the subpellicular network of Toxoplasma gondii tachyzoites (Khater, E.I., et al. 2004, J. Cell. Biol. 167, 425-32) . See also the phenotype analyses of the mutant  RMgm-147 lacking expression of IMC1b. 

Phenotype
The phenotype analyses indicate that expression of IMC1b occurs predominantly in the (developing) ookinete stage.
As the ookinete develops by forming a protrusion of the spherical zygote, a developmental stage called retort, strong fluorescence became localized to the periphery of the protrusion corresponding to the newly forming ookinete but not to the zygote part of the retort . These observations argue against the targeting of IMC1b to the plasma membrane; in this scenario the protein would be localized to the periphery of entire retort, which is not the case. The localized peripheral fluorescence did not extend all the way to the anterior end of the developing ookinetes. These observations are consistent with a localization of IMC1b to the ookinete pellicle structure, which support the prediction that IMC1b is a membrane skeleton protein.
See also the phenotype analyses of the mutant  RMgm-147 lacking expression of IMC1b. 

Additional information

Other mutants
RMgm-147: A mutant lacking expression of IMC1b
RMgm-148: A mutant lacking expression of IMC1a (inner membrane complex protein 1a)
RMgm-600: A mutant expressing a GFP-tagged form of IMC1h
RMgm-601: A mutant lacking expression of IMC1h
RMgm-602: A mutant lacking expression of both IMC1h and IMCb