The mutation results in a product lacking the C1 and Citron Homology domains and the last portion of the coiled-coil region.
Amino acid replacement: R1093term.
Amino acid replacement: ?1093term.
Nucleotide substitution: T4013A.
C12510777T
R1093term | sti-PA; R1097term | sti-PB
R1093term
Site of nucleotide substitution in mutant inferred by FlyBase based on reported amino acid change.
abnormal size | larval stage (with sti3)
abnormal size | larval stage (with sti4)
imaginal disc (with sti3)
imaginal disc (with sti4)
neuroblast & chromosome
neuroblast & chromosome (with sti4)
neuroblast & chromosome (with sti5)
neuroblast & condensed chromosome
sti4/sti1 mutant third instar larval brains do not exhibit a mitotic index higher than in wild-type. However, they exhibit a much higher level of polyploid neuroblasts. Approximately 24.2% of sti4/sti1 cells are 4N, 20.9% 8N, and 16.5% over 8N. Approximately 3.3% of sti4/sti1 cells exhibit a hypercondensed phenotype. sti1 homozygous, sti1/sti3, sti1/sti4, and sti1/Df(3L)F10 larvae have very small imaginal discs and are lethal at the prepupal stage. sti5/sti1 mutant third instar larval brains do not exhibit a mitotic index higher than in wild-type. However, they exhibit a much higher level of polyploid neuroblasts. Approximately 41.9% of sti5/sti1 cells are 4N, 19.3% 8N, and 3.2% over 8N. sti5/sti1 third instar neuroblasts do not exhibit a hypercondensed phenotype.
In trans to a deficiency, mitotic chromosomes (both sisters and heterologues) stuck together and show metaphase delay; "successful" anaphase fragments the chromosomes.
Imaginal discs of homozygous larvae are small.
imaginal discs small 77% highly polyploid cells; no mitotic block
Shearn and Garen.
Based on lethal phase analysis the following sti alleles can be ranked from the most severe to the weakest as follows: sti3 > sti1 = sti2 = sti4 > sti5.