FlyBase curator comment: this entry is used to capture phenotypic information when the particular allele (or allele combination) used by the author could not be determined but the context of the experiment suggests that the phenotype being described is some kind of loss of function.
In chb mutant neuroblasts display various degrees of disorganisation of the mitotic apparatus. Spindle microtubules rea often irregular in shape. When cells are able to organise bipolar spindles, spindle poles contain an irregular number of ring-like structures. Many cells are found to contain only a single microtubule organising centre (MTOC), Some of MTOCs contain multiple ring-like structures, and others are diffuse ball-like structures.