2 MODES OF TRANSVECTION - ENHANCER ACTION IN TRANS AND BYPASS OF A CHROMATIN INSULATOR IN CIS

Citation
Jr. Morris et al., 2 MODES OF TRANSVECTION - ENHANCER ACTION IN TRANS AND BYPASS OF A CHROMATIN INSULATOR IN CIS, Proceedings of the National Academy of Sciences of the United Statesof America, 95(18), 1998, pp. 10740-10745
Citations number
71
Categorie Soggetti
Multidisciplinary Sciences
ISSN journal
00278424
Volume
95
Issue
18
Year of publication
1998
Pages
10740 - 10745
Database
ISI
SICI code
0027-8424(1998)95:18<10740:2MOT-E>2.0.ZU;2-T
Abstract
Ed Lewis introduced the term ''transvection'' in 1954 to describe mech anisms that can cause the expression of a gene to be sensitive to the proximity of its homologue. Transvection since has been reported at an increasing number of loci in Drosophila, where homologous chromosomes are paired in somatic tissues, as well as at loci in other organisms. At the Drosophila yellow gene, transvection can explain intragenic co mplementation involving the yellow(2) allele (y(2)). Here, transvectio n was proposed to occur by enhancers of one allele acting in trans on the promoter of a paired homologue. In this report, we describe two ye llow alleles that strengthen this model and reveal an unexpected, seco nd mechanism for transvection. Data suggest that, in addition to enhan cer action in trans, transvection can occur by enhancer bypass of a ch romatin insulator in cis. We propose that bypass results from the topo logy of paired genes. Finally, transvection at yellow can occur in gen otypes not involving y(2), implying that it is a feature of yellow its elf and not an attribute of one particular allele.