Details

Autor(en) / Beteiligte

• Lim, Bomyi
• Heist, Tyler
• Levine, Michael
• Fukaya, Takashi

Titel

Visualization of Transvection in Living Drosophila Embryos

Ist Teil von

• Molecular cell, 2018-04, Vol.70 (2), p.287-296.e6

Ort / Verlag

United States: Elsevier Inc

Erscheinungsjahr

2018

Link zum Volltext

Quelle

Free E-Journal (出版社公開部分のみ）

Beschreibungen/Notizen

• How remote enhancers interact with appropriate target genes persists as a central mystery in gene regulation. Here, we exploit the properties of transvection to explore enhancer-promoter communication between homologous chromosomes in living Drosophila embryos. We successfully visualized the activation of an MS2-tagged reporter gene by a defined developmental enhancer located in trans on the other homolog. This trans-homolog activation depends on insulator DNAs, which increase the stability—but not the frequency—of homolog pairing. A pair of heterotypic insulators failed to mediate transvection, raising the possibility that insulator specificity underlies the formation of chromosomal loop domains. Moreover, we found that a shared enhancer co-activates separate PP7 and MS2 reporter genes incis and intrans. Transvecting alleles weakly compete with one another, raising the possibility that they share a common pool of the transcription machinery. We propose that transvecting alleles form a trans-homolog “hub,” which serves as a scaffold for the accumulation of transcription complexes. [Display omitted] •Insulators increase the stability, but not the frequency, of allele-allele pairing•The gypsy insulator functions in an orientation-independent manner•A shared enhancer co-activates linked PP7 and MS2 reporter genes in cis and in trans•Linked reporter genes compete for shared resources during transvection Lim et al. explore a process called transvection in living Drosophila embryos, whereby enhancers on one homolog activate transcription units on the other homolog. They show that insulators facilitate transvection by stabilizing allele-allele pairing. Surprisingly, a shared enhancer coactivates a cis-linked PP7 reporter gene along with a trans-linked MS2 reporter contained on the other homolog. This coactivation is consistent with emerging evidence for transcription “hubs” containing clusters of RNA polymerase II and associated activators.