[Chow KL] Transformation of thick ray 6 to a thin ray, which is anteriorly displaced and fuses with ray 4 (>95%). A tenth ray derived from hypodermal cell T.apapa is found in about 50% of the sides scored in all three alleles. mab-21(bx53)/yDf10 is embryonic lethal. Both males and hermaphrodites have slightly shorter body length (~85% of wild type)
[C.elegansII] bx53 : transformation of thick ray 6 to a thin ray, which is anteriorly displaced and fuses with ray 4 (>95%). Tenth ray derived from T.apapa, between rays 5 and 7, is found in ~50% of sides scored. Both males and hermaphrodites have slightly shorter body length (~85% of wild type); reduced brood size; males backward Unc, reduced mating efficiency. Mosaic focus cell autonomous for R6, non-autonomous for T.apapa. Probable hypomorph, bx53/Df is embryonic lethal. OA2: bx41, sy155 (similar). Cloned: encodes predicted 386 aa novel protein. [Baird et al. 1991; Chow et al. 1995; KC; EM; PS]
mab-21 encodes a novel protein that is a member of a highly conserved family of proteins with Drosophila and vertebrate orthologs; MAB-21 is cell-autonomously required for specifying the identity of sensory ray 6 in the male tail, and also for backward locomotion, normal body morphology, fecundity, and embryonic morphogenesis; MAB-21 expression begins in embryonic hypodermal cells and continues in larval and adult animals in hypodermis, anterior and ventral cord neurons, some body wall muscles, and ray cells.
Involved in cell fate commitment; embryo development; and nematode male tail mating organ morphogenesis. Expressed in several structures, including PVC; VA2; hyp7 syncytium; ray 6; and sensory neurons. Human ortholog(s) of this gene implicated in coloboma and syndromic microphthalmia 14. Is an ortholog of human MAB21L1 (mab-21 like 1) and MAB21L2 (mab-21 like 2).