|Feature type||allele||Associated gene||Dmel\brat|
|Map ( GBrowse )|
|Mutagen||ethyl methanesulfonate, formaldehyde|
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|Nature of the Allele|
|Mutations Mapped to the Genome|
|Associated Sequence Data|
|Nature of the lesion|
Amino acid replacement: Q779@.
|Phenotype Manifest In|
brat/brat[DG19310] larval brains contain supernumerary type II neuroblasts. brat/brat[k06028] larval brains contain supernumerary type II neuroblasts.
brat germ line clones dispay an increased growth phenotype, with larger cells than wild-type. There is an increase in the number of germline stem cells in these mutants.
In late third instar brat11 mutant larvae, brain hemispheres are markedly enlarged and characterized by cellular overgrowth whereas ventral ganglia appear normal. The central brain is characterized by dense cellular masses of numerous small and pleiomorphic cells in addition to a limited number of large cells. At earlier larval stages, brain hemispheres, brat11 mutants brain hemispheres are the same overall size as wild-type larvae. brat11 clones in the central brain of third instar larvae populate large areas of the brain hemispheres and are up to ten times larger than wild-type central brain clones: over 80% of the mutant clones comprise 200-1000 cells, while wild-type clones comprise >100 cells. In the early larval instar, brat11 clones are clearly distinguishable and separated from one another, but by the late third instar almost all of the central brain appears to be covered by an indistinguishable clonal cell mass. Cells in brat11 clones lack axonal processes. In the ventral ganglia, brat11 clones are recovered at a similar frequency to wild-type clones. brat11 clones induced in first instar larvae appear dramatically enlarged in size and cell number in the adult brain and appear to be mitotically active (according to phosphorylated His3 staining).
In brat homozygous mutant larvae there is a dramatic increase in neuroblast number, over 500 by 96 hours after larval hatching and an estimated several thousand by 120 hours after larval hatching. This corresponds to a reduction in elav staining, indicating ectopic neuroblast generation at the expense of neurons. brat neuroblasts generate GMC-sized progeny that are cell cycle delayed and continue to express neuroblast markers; some of these 'GMCs' differentiate into neurons, but many appear to develop into proliferative neuroblasts.
brat11 homozygous somatic clones in third instar larvae are consistently larger than wild-type. the cells themselves are larger than individual wild-type cells. Mutant cells also have nucleoli that are 18 to 33% larger than wild-type cells, mutant dells contain 1.6 times more rRNA than control cells.
The median survival of adult hosts transplanted with brat11/brat14 brain fragments is reduced compared to adult hosts transplanted with wild-type brain fragments. Cells from transplanted brat11/brat14 brain fragments form at least one secondary tumour in the wild-type host in 84% of cases. Imaginal discs from brat11/brat14 larvae form secondary tumours in 53% of hosts.
Hemizygous larval brain tissue transplanted into the abdomens of adult female hosts shows unrestrained and invasive growth.
brat11 has neuroanatomy defective | somatic clone phenotype, suppressible by prosScer\UAS.cMa/Scer\GAL4αTub84B.PL
bratDG19310/brat11 has neuroanatomy defective | larval stage phenotype, suppressible by klu[+]/kluunspecified
|Phenotype Manifest In|
brat11 has embryonic/larval brain | somatic clone phenotype, suppressible by prosScer\UAS.cMa/Scer\GAL4αTub84B.PL
bratDG19310/brat11 has type II neuroblast | supernumerary | larval stage phenotype, suppressible by klu[+]/kluunspecified
klu[unspecified]/+ strongly suppresses the formation of supernumerary type II neuroblasts which is seen in brat/brat[DG19310] larval brains. The formation of supernumerary type II neuroblasts is suppressed in homozygous klu[unspecified] type II neuroblast clones in brat/brat[k06028] larval brains.
Expression of prosScer\UAS.cMa, under the control of Scer\GAL4αTub84B.PL, in brat11 mutant larval clones significantly suppresses the overproliferation phenotype in these clones in the central larval brain. Over 90% of Scer\GAL4αTub84B.PL>prosScer\UAS.cMa, brat11 clones in the central brain have <100 cells, while over 80% of brat11 clones have 200-1000 cells.
|Complementation & Rescue Data|
|Stocks ( 0 )|
|Notes on Origin|
|External Crossreferences & Linkouts|
|Synonyms & Secondary IDs ( 3 )|
|Secondary FlyBase IDs|
|References ( 12 )|