Expression of a fragment of w genomic DNA with a 2.2kb deletion of 3' flanking sequences and a reduction in the size of the largest intron to 356bp is driven by a 388bp fragment of an Hsp70 gene.
Construct: A 'mini-white' gene constructed by deletion of the XbaI-HindII fragment from the long 5' intron. Carried by the W6 and W8 series of vectors.
Eye colour: red even in the absence of heatshock.
All flies carry the w1118 mutation, all observed pigmentation is due to expression of the w transgene. P{hsFLP} P{FRT(whs)} heat induced expression during third instar causes mosaic pattern in the anterior and posterior adult eye. A stripe exhibiting little loss of w pigmentation lies slightly anterior to the morphogenetic furrow, this is due to these cells exhibiting a slightly feeble response to heat shock (as seen from P{hsp70-lacZ} expression pattern). P{FRT(whs)} P{hsFLP} bearing flies heat shocked 6 hours after puparium formation exhibit the same level and pattern of pigmentation as individuals not heat shocked. w+mW.hs transcription at this stage is without phenotypic consequence. The coding region of w+mW.hs located in the chromosome, P{FRT(whs)}, or extrachromosomally can respond to the mechanism of dosage compensation, expressed more strongly in males than in females. Some lines of P{FRT(whs)} exhibit position effect variegation; enhanced in XO males and suppressed by Su(var)205502. P{hsFLP} and P{70FLP} induced excision 6 hours after puparium formation alleviates the variegating position effects. Lines carrying P{FRT(whs)} near the heterochromatin require daily heat shocks from 18 hours after puparium formation for 5-6 days to give the most reversion. P{70FLP} mediated excision of some heterochromatic insertion lines 6-30 hours after egg laying gives rise to entirely white-eyed adults, other lines exhibit a reduction in the rate of excision so show areas of pigment. Induction during third larval instar causes loss in the anterior portion of the eye.
Transformant heat shocked males exhibit homosexual courtship behaviour.
Wild type eye pigmentation.
The eye pigmentation of Df(1)w67c2 homozygotes carrying w+mW.hs is reduced if the flies are also carrying two copies of LTSV\RBZhs.w and are heat shocked for 1 hour at 37oC every 12 hours throughout development.
Eye colour: red, as homozygote. Eye colour: orange eyes that darken and become slightly mottled with age, as heterozygote.
AGO2414, w[+]/w+mW.hs has abnormal eye color phenotype
AGO2414, w+mW.hs has abnormal eye color phenotype
w+mW.hs has phenotype, suppressible by Su(var)205502
The progeny of male flies homozygous for w+mW.hs (inserted into centric heterochromatin of the second chromosome-39C4) mated with AGO2414 homozygous females have different eye colour, but a relatively uniform pigmentation across the eye, with little evidence of variegation, indicating heterochromatic silencing.
The presence of Su(var)2051, Su(var)2052 or additional heterochromatin provided by an attached X suppress position effect variegation (PEV) of lines with insertions in centromeric regions or in the fourth chromosome. Insertions near the telomeres 2L, 2R or 3R show no suppression. Variegating transgenes show a reduction in accessibility to restriction enzyme digestion. This suggests that the chromatin packaging of an insert showing PEV is altered. Pericentric transgenes are packaged in a more regular array than euchromatic transgenes.
The w gene is turned on in the P{FRT(whs)} construct and Scer\FLP1-mediated expression produces a functional extrachromosomal w gene that can be expressed in non-dividing cells but is lost in dividing cells. Carried in episome eFRT-w.G.
Carried in episome eFRT-w.G.