A396582T
K136term | sc-PA
K136term
At 18oC 76% of expected scsisB-2 homozygotes survive to adulthood, but this drops to 35% when these animals are raised at 25oC. 50-89% of scsisB-1 homozygous adults lack upper humeral and anterior orbital bristles. With variable penetrance, scsisB-1/In(1)sc8Lsc4R adults lack ocellar, anterior orbital, posterior orbital, postvertical, upper humeral, anterior supraalar, notopleural, posterior postalar, lower humeral and presutral bristles. With variable penetrance scsisB-1/Df(1)sc19 adults lack all head bristles apart from the posterior vertical bristles, and all bristles of the dorsal thorax apart from the posterior notoplural, posterior dorsocentral and scutellar bristles.
Temperature-sensitive mutation.
Original hypomorphic allele recovered as a reversion of sc3 to nearly wild-type ac and sc phenotype in hemizygote and homozygote. Locus also characterized by dominant effects of deficiencies and duplications of the ASC region and later by mutant alleles sc10-1 and acHw-49c that affect ASC functions more than scsisB-1 functions. scsisB-1 reduces viability of homozygous females and hemizygous females are lethal; yet hemizygous males fully viable. Dominant synergistic female-specific lethal interactions with loss-of-function alleles of Sxl, sisA, and/or maternal da; magnitude of viability effects depends on genetic background and inversely correlates with background effects on male-lethal effects; interactions temperature-dependent, generally more extreme at higher temperatures. Female viability effects suppressed by gain-of-function SxlM1 allele and by duplications of Sxl+ or sisA+. Duplication of scsisB-1+ male-lethal in combination with duplication of Sxl+ and/or sisA+, more so at lower temperatures. Male lethality of duplication combinations suppressed by Sxl-. Phenotype of 2X;3A intersexes strongly dependent on dose of scsisB-1+. The dose-dependent interactions of this gene identify it as a positive regulator of Sxl+ and part of the numerator of what is referred to as the X/A balance, the primary sex-determination signal. This is a character it shares with sisA. RK2.
Temperature shift experiments showed that lowering sc activity in the presence of extra copies of dpn+ results in the death of females but not males.
The viability of homozygous females ranges from 100% at 18oC to less than 1% at 29oC.
Flies show a mild bristle phenotype. Sex determination is affected much more strongly by scsisB-1 than is neurogenesis, and the two aspects show different temperature dependencies. Temperature sensitive period for feamle lethal affect corresponds to peak of sc expression between nuclear cycles 9 and 14 in the embryo.
Interacts with RpII140wimp maternal effect.
Homozygous females show reduced viability hemizygous female lethal.
scsisB-1, sisA[+]/sisA1 has partially lethal - majority die | dominant | female phenotype, enhanceable | maternal effect by mle1/mle[+]
scsisB-1, sisA[+]/sisA1 has partially lethal - majority die | dominant | female phenotype, enhanceable | maternal effect by msl-1L60/msl-1[+]
scsisB-1, sisA[+]/sisA1 has partially lethal - majority die | dominant | female phenotype, enhanceable | maternal effect by msl-2[+]/msl-21
scsisB-1, sisA[+]/sisA1 has partially lethal - majority die | dominant | female phenotype, enhanceable | maternal effect by msl-3[+]/msl-31
scsisB-1, sisA[+]/sisA1 has partially lethal - majority die | dominant | female phenotype, enhanceable by roX1[+]/lncRNA:roX1ex6
scsisB-1, sisA[+]/sisA1 has partially lethal - majority die | dominant | female phenotype, enhanceable by lncRNA:roX2unspecified/roX2[+]
msl-3[+]/msl-31, scsisB-1, sisA[+]/sisA1 has lethal | dominant | female | maternal effect phenotype, suppressible | maternal effect | partially by SxlM1/Sxl[+]
scsisB-1 is a suppressor | partially of lethal | female limited phenotype of MycP1
scsisB-1 is a suppressor | partially of lethal | female limited phenotype of Mycdm-1
scsisB-1 is a suppressor | partially of lethal | female limited phenotype of MycP0
scsisB-1, sisA[+]/sisA1 has partially lethal - majority die | dominant | female phenotype
msl-31, sc[+]/scsisB-1 has lethal | female | maternal effect | heat sensitive phenotype
sc[+]/scsisB-1, sisA1 has partially lethal - majority die phenotype
scsisB-1, sisA[+]/sisA1 has partially lethal - majority die | dominant phenotype
scsisB-1 is a suppressor | partially of macrochaeta | ectopic phenotype of hhbar3
Approximately 24% of scsisB-1 dm1 trans-heterozygous female offspring from dm1 fathers mated to scsisB-1 females survive.
Approximately 90% of scsisB-1 dmP0 trans-heterozygous female offspring from dmP0 fathers mated to scsisB-1 mothers survive.
Approximately 76% of scsisB-1 dmP1 trans-heterozygous female offspring from dmP1 fathers mated to scsisB-1 mothers survive.
scsisB-1 sisA1/+ females show reduced viability compared to their male siblings.
One maternally-derived copy of either mle1, msl-1L60, msl-21 or msl-31 significantly reduces the viability of scsisB-1 sisA1/+ females so that they show almost complete lethality. One paternally-derived copy of either mle1, msl-1L60, msl-21 or msl-31 significantly reduces the viability of scsisB-1 sisA1/+ females, although this zygotic effect is generally weaker than the maternal one.
The viability of scsisB-1/+ females raised at the non-permissive temperature of 29[o]C is significantly reduced if they also carry one maternally-derived copy of msl-31.
One paternally-derived copy of mof2, roX1ex6 or roX2unspecified reduces the viability of scsisB-1 sisA1/+ females.
The almost complete lethality of scsisB-1 sisA1/+ females carrying a maternally-derived copy of msl-31 is significantly rescued (to 72.8% viability) by a maternally-derived copy of SxlM1.
scsisB-1 is not rescued by scB23.lacZ
Sturtevant.
Revertant. \partial
The temperature sensitive period begins at nuclear cycle 9 and ends at the beginning of nuclear cycle 14.
Originally designated "sc3-1" by Sturtevant, renamed sis-b by Cline.
Lethal phenotype is due to failure to properly activate Sxl-Pe.