Lethality occurs during third instar larval or pupal stages. Mutants exhibit visible disc abnormalities: very small or no discs. Clones cannot be induced in wild type discs. In tergites, clones with normal size and frequency are recovered. Clones cannot be recovered in the wing disc.
Homozygous third instar larvae contain numerous melanotic tumours. The hemolymph contains an increased number of blood cells compared to wild-type, these cells consisting mainly of podocytes and some lamellocytes. The lymph glands are hypertrophied and have a high rate of cell proliferation. Mutant imaginal discs are smaller than wild-type, due to a reduced rate of cell proliferation, and show abnormal morphogenesis. Cell proliferation is abnormal in the central nervous system.
Lymph glands initially appear normal in third instar larvae, but in older larvae they increase in size and form loose masses of aggregated hemocytes associated with the aorta, or disperse throughout the body cavity forming nodules. Some of these nodules become melanised as the larvae age. These melanotic tumours are often associated with the midgut/hindgut boundary or Malpighian tubules. 4% of hemocytic tumour tissue gives rise to tumorous outgrowths when transplanted into the abdomen of a wild-type female. Mutants show overgrowth of the gonads, and testes are filled with small single cells, lacking spermatogonial cysts. Most imaginal discs (including wing, leg, haltere and eye/antenna discs) are reduced in size, and have an abnormal shape and folding pattern, although they may become overgrown in very old larvae. In contrast, the genital discs are larger than normal. Brain organisation is abnormal; the hemispheres are smaller, and the ventral ganglion is often longer than wild-type. Polytene larval tissues, including the ring gland, are reduced in size, but their morphology is normal. 13% of overgrown genital disc tissue gives rise to tumorous outgrowths when transplanted into the abdomen of a wild-type female. Implanted fragments of other mutant tissues do not give rise to visible outgrowths.
Hyperplastic lymph glands grow as diffuse masses that fill the anterior body cavity, melanotic masses are dispersed all over the body. Mutant brains are smaller than wild type, discs are also smaller with abnormal folding.
Separable from: Penk14401a. The larval lethality and overgrowth of hematopoietic tissue phenotypes originally described as being due to Penk14401a in FBrf0082252 and FBrf0082712 have been found to be due to a second site mutation (oho31k14401b).
The mutant phenotypes of "l(2)k14401" homozygotes (which carry both oho31k14401b and P{lacW}Penk14401a) described in FBrf0082712 and FBrf0082252 are all due to the oho31k14401b mutation and are not due to the P{lacW}Penk14401a insertion.
Complements: l(2)k06324k06324.
FlyBase curator comment: "oho31" phenotype (overgrown hematopoietic tissues and larval lethality) in the "l(2)k14401" insertion line is stated in FBrf0082252 to be due to an effect on the "Pen" gene, however, FBrf0149010 states that the "oho31" mutant phenotype is caused by a second site mutation separable from the insertion in "Pen" in the "l(2)k14401" insertion line.
FlyBase curator comment: "oho31" phenotype (overgrown hematopoietic tissues and larval lethality) in the "l(2)k14401" insertion line is stated in FBrf0082712 to be due to an effect on the "Pen" gene, however, FBrf0149010 states that the "oho31" mutant phenotype is caused by a second site mutation separable from the insertion in "Pen" in the "l(2)k14401" insertion line.