Amino acid replacement: E426K.
Nucleotide substitution: G1276A.
G9683175A
G1276A
E426K | alphaTub67C-PA
E426K
centrosome & cleavage nucleus
microtubule & oocyte
microtubule & oocyte (with Df(3L)55)
spindle & cleavage nucleus
Eggs derived from heterozygous females either do not commence embryogenesis or it occurs abnormally; several of the cleavage nuclei fail to migrate into the egg cortex, leaving large areas free of nuclei.
Ooplasmic streaming does not occur in the egg primordia of αTub67Ckav-21g/+ or αTub67Ckav-21g/Df(3L)55 females. This leads to a gradual accumulation of the yolk granules in the posterior oocyte cytoplasm, leaving the entire anterior cytoplasm free of yolk granules.
The oocytes of αTub67Ckav-21g/+ or αTub67Ckav-21g/Df(3L)55 females do contain numerous and long microtubules, however they are not organised into parallel bundles as occurs in wild-type females.
Although ooplasmic streaming is completely abolished in the egg primordia of αTub67Ckav-21g/+ females and αTub67Ckav-21g/Df(3L)55 females, the motion of those lipid droplets that move independently of streaming still occurs in the mutant egg chambers. The average velocity of the lipid droplets is significantly lower in mutant early stage 12 egg chambers compared to controls, and the average dwell time and average run length are also decreased.
Embryogenesis fails to commence in about 20% of embryos laid by αTub67Ckav-21g/+ females. In about 30% of these embryos, development ceases following nuclear division 8 - prior to migration of cleavage nuclei to the periphery. In the remaining 50% of embryos, 1-3 islands of cleavage nuclei migrate to the periphery where they continue to divide and cellularize and, at least in some cases, differentiate into larval structures including head skeleton and ventral setae. In areas of the blastoderm cortex that remain devoid of cleavage nuclei, centrosomes fail to separate and are associated with tassels of microtubules rather than sitting at either end of a spindle.
Embryogenesis arrests before embryonic cycle 5 in embryos laid by αTub67Ckav-21g/Df(3R)55 or αTub67Ckav-21g/Df(3L)21mrx1 mothers.
Female viability is reduced and male fertility is not reduced. Embryos exhibit severe head lesions.
αTub67Ckav-21g has organism | cleavage stage | maternal effect phenotype, enhanceable by Khc[+]/Khc8
αTub67Ckav-21g has organism | cleavage stage | maternal effect phenotype, enhanceable by +/Df(3L)ED202
αTub67Ckav-21g has organism | cleavage stage | maternal effect phenotype, non-enhanceable by Dhc64C[+]/Dhc64C4-16
αTub67Ckav-21g has organism | cleavage stage | maternal effect phenotype, non-enhanceable by Gl[+]/DCTN1-p150Gl-1
αTub67Ckav-21g has organism | maternal effect | cleavage stage phenotype, suppressible by ncd[+]/ncd1
αTub67Ckav-21g has organism | maternal effect | cleavage stage phenotype, non-suppressible by Dhc64C[+]/Dhc64C4-16
αTub67Ckav-21g has organism | maternal effect | cleavage stage phenotype, non-suppressible by Gl[+]/DCTN1-p150Gl-1
The early cleavage defects seen in embryos derived from αTub67Ckav-21g/+ females occur in a significantly larger proportion of embryos if the females also carry one copy of either Khc8 or Df(3L)ED202.
The early cleavage defects seen in embryos derived from αTub67Ckav-21g/+ females are partially suppressed by ncd1/+, with the embryos reaching a later stage of development (43.3% of 3-4 hour embryos derived from the double heterozygous females resemble a normal cellular blastoderm).
The early cleavage defects seen in embryos derived from αTub67Ckav-21g/+ females are not altered if the females also carry one copy of either Dhc64C4-16 or Gl1.
αTub67Ckav-21g is partially rescued by αTub67C+tVa
A higher percentage of αTub67Ckav-21g/+ embryos show signs of differentiation if they also carry Dp(3;3)S2a2 or αTub67CtVa.
