Using TRiP lines

TRiP constructs are injected into the following stocks

  • older stock collections
    • y sc v; attP2 (genotype: y[1] sc[1] v[1]; P{y[+t7.7]=CaryP}attP2)
    • y sc v; attP40 (genotype: y[1] sc[1] v[1]; P{y[+t7.7]=CaryP}attP40)
  • newer stock collections
    • y v; attP2 (genotype: y[1] v[1]; P{y[+t7.7]=CaryP}attP2)
    • y v; attP40 (genotype: y[1] v[1]; P{y[+t7.7]=CaryP}attP40)

These stocks can be used as controls, but other control lines are also available here.

TRiP stock phenotype

  • wildtype cuticle color, yellow+ (y+) indicates that the attP site is present
  • wildtype eye color, vermillion+ (v+) indicates that the hairpin is present
  • loss of scutellar bristles, scute- (sc-) indicates the presence of the y sc v  X chromosome
    • note that the TRiP no longer injects into sc mutant embryos
    • thus newer TRiP stocks lack the sc bristle phenotype

The genotype of each TRiP stock can be found in the downloadable excel sheet on the stocks page.

Please note that TRiP stocks do not contain a mini-white marker. For the TRiP stocks that have recessive sc on the X chromosome, the allele of sc used is not very penetrant if grown at 18C, but is fully penetrant at 25C.


  • 5-10% of the TRiP stocks are homozygous lethal
  • lethal stocks are maintained over balancers
  • we attribute lethality to naturally occurring second site lethals on the 2nd or 3rd chromosomes
  • non-lethal but unhealthy stocks are also maintained over balancers to protect the integrity of the stock
  • if the balancer is present in all flies, then 50% of the progeny will not carry the hairpin
  • second site lethal can be recombined away from the attP insertion site if necessary
  • when examining embryos, larvae or pupae, switch balancer to one containing marker present at the relevant stage of development

Expressing TRiP lines

  • any GAL4 line can be used to activate transcription of a TRiP hairpin under UAS control
  • without a GAL4 driver present you should not get expression of the hairpin and thus you should not see any knock down phenotype
  • if phenotype observed in an otherwise wildtype fly, then the transgene is somewhat "leaky" (this is rare)
  • GAL4 drivers commonly used by the TRiP are listed in the TRiP Toolbox and can be obtained from the BDSC
  • visit the RNAi Stock Validation & Phenotypes (RSVP) page for data on TRiP stock quality (knockdown ability, phenotypes, etc.)

 Enhancing knockdown with UAS-dicer2

  • drivers containing UAS-dicer2 are included in the TRiP Toolbox
  • for TRiP stocks constructed in the VALIUM1 vector, maximum knockdown will only be attained if UAS-dicer2 is carried in the GAL4 driver
  • TRiP stocks constructed in the VALIUM10, VALIUM20, VALIUM21 or VALIUM22 vectors do not require inclusion of UAS-dicer2 with the Gal4.
  • to determine which VALIUM vector your TRiP stock uses please refer to the list of current TRiP stocks at the TRiP RNAi fly stocks page
  • For expression of TRiP lines during oogenesis, see GAL4-UAS in the germline

 Off target effects (OTE)

  • short hairpin microRNAs in VALIUM20, VALIUM21 and VALIUM22 are not expected to have any OTE
  • for long hairpins in VALIUM1 and VALIUM10 you can predict the off-targets by following the protocol below
    • Input your gene name into the Updated Targets of RNAi Reagents (UP-TORR) search tool
    • Under “Off-target search options” select “Check off-target genes for matches greater than or equal to” and select the number of base pairs
    • Click submit, find the long hairpin line in the list of reagents, and click on the number in the OTE column.


  • if a TRiP stock does not produce an expected phenotype please email the TRiP and/or report your result on the RNAi Stock Validation Project (RSVP) feedback page and let us know
  • ineffective stocks will be removed from the collection and tested by the TRiP team
  • if sufficient knockdown is not observed, a new set of oligos will be designed and a new construct generated to replace the TRiP stock