Hemizygous larvae have small imaginal discs and overgrown lymph glands. The concentration of circulating hemocytes in third instar larvae is significantly increased compared to controls and the fraction of circulating hemocytes that are undergoing cell division is also increased. The number of crystal cells per larva is significantly reduced compared to controls. The larvae show a significant increase in a blood cell type ("podocytes") with large pseudopod-like extensions compared to controls. These cells appear pear-shaped or spindle-shaped. Mutant larvae contain an increased fraction of lamellocytes (2.3%) compared to controls (0.2%). 60% of hemizygous lymph glands transplanted into wild-type females show an increase in size 5 days after transplantation, in contrast to wild-type lymph gland transplants, which do not show growth.
Hemizygous larvae raised at 19oC reach normal size with a slight delay. Hemizygous larvae raised at 25oC are smaller than normal and develop slowly. The larvae remain at the wandering stage for up to 7 days without forming pupae. The imaginal discs and brain are reduced in size. The eye-antennal, leg and wing discs appear more deformed than the haltere or genital discs. Does not rescue the lack of abdominal segment differentiation seen in the progeny of hb4 nosL7/nosL7 females. Almost all third instar larvae have melanotic pseudotumours.
mxcG9/mxc1 females have fewer egg chambers than wild-type flies, but are fully fertile and fecund. mxcM1/mxc1 and mxcG46/mxc1 females do not lay eggs. Some egg chambers contain the normal number of nurse cells, but oogenesis appears arrested before stage 7-8. Egg chambers degenerate in older flies.
Larvae show invasive blood cell tumors. Rare adult escapers show variably penetrant homeotic transformations. The eye transformation resembles that of Dfd1. Female heterozygotes with mxcG46 or mxcG43 are devoid of germ line. Most mxcG48 heterozygotes with mxc1 or mxcSO die in the third instar with blood cell tumors.
In contrast to wild-type, differentiated blood cells are produced throughout the third larval instar stage in homozygotes, causing a 300-400 fold increase in the size of the individual hematopoietic lobes. Cell division in the anterior hematopoietic lobes is increased. Many of these differentiated blood cells are released into the haemolymph throughout the third larval instar stage, resulting in an increase of free blood cells. The blood cells encapsulate and melanise parts of the posterior fat body and gut, and they invade and partially destroy the imaginal disc epithelia. The central nervous system and gonads appear smaller than wild-type, and the larvae appear transparent due to the reduced amount of fat body. All primordial blood cells found in wild-type larval hematopoietic organs are also found in the hematopoietic organs of homozygous larvae. Plasmatocytes, podocytes and lamellocytes are also detected in the hematopoietic organs of homozygous larvae, in contrast to wild-type. Within the tumorous hematopoietic masses the primordial blood cells are tightly packed, while the plasmatocytes, podocytes and lamellocytes are loosely arranged. Mutant prohemocytes show a slight increase in the number of Golgi bodies, and primary and secondary lysosomes compared to wild-type, and virus-like particles (vlps) are seen in the nuclei and cytoplasm. Mutant proplasmatocytes have increased numbers of primary and secondary lysosomes, and their nuclei are often lobulated and contain vlps. Mutant procrystal and crystal cells are extremely rare in the hematopoietic organs and hemolymph. Mutant plasmatocytes contain more mitochondria, primary and secondary lysosomes and phagocytic vesicles than wild-type. Their nuclei are deformed and contain large numbers of vlps. Mutant podocytes have extensive cytoplasmic processes. Mutant lamellocytes contain a large number of primary and secondary lysosomes. Their nuclei have an irregular shape and contain many vlps. Lamellar bodies are common in mutant plasmatocytes, podocytes and lamellocytes in contrast to wild-type. The composition of the mutant larval hemolymph resembles a wild-type prepupa more closely than a wild-type larva, containing 30-40% plasmatocytes, 45% podocytes and 15% lamellocytes.