Abstract
The Ultrabithorax (Ubx) gene of Drosophila melanogaster contains two functionally distinguishable regions: the protein-coding Ubx transcription unit and, upstream of it, the transcribed but non-protein-coding bxd region. Numerous recessive, partial loss-of-function mutations which appear to be regulatory mutations map within the bxd region and within the introns of the Ubx transcription unit. In addition, mutations within the Ubx unit exons are known and most of these behave as null alleles. Ubx(1) is one such allele. We have confirmed that, although the Ubx(1) allele does not produce detectable Ubx proteins (UBX), it does retain other genetic functions detectable by their effects on the expression of a paired, homologous Ubx allele, i.e., by transvection. We have extended previous analyses made by E. B. Lewis by mapping the critical elements of the Ubx gene which participate in transvection effects. Our results show that the Ubx(1) allele retains wild-type functions whose effectiveness can be reduced (1) by additional cis mutations in the bxd region or in introns of the Ubx transcription unit, as well as (2) by rearrangements disturbing pairing between homologous Ubx genes. Our results suggest that those remnant functions in Ubx(1) are able to modulate the activity of the allele located in the homologous chromosome. We discuss the normal cis regulatory role of these functions involved in trans interactions between homologous Ubx genes, as well as the implications of our results for the current models on transvection.
Full Text
The Full Text of this article is available as a PDF (3.0 MB).
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Babu P., Selvakumar K. S., Bhosekar S. Studies on transvection at the bithorax complex in Drosophila melanogaster. Mol Gen Genet. 1987 Dec;210(3):557–563. doi: 10.1007/BF00327212. [DOI] [PubMed] [Google Scholar]
- Beachy P. A., Helfand S. L., Hogness D. S. Segmental distribution of bithorax complex proteins during Drosophila development. Nature. 1985 Feb 14;313(6003):545–551. doi: 10.1038/313545a0. [DOI] [PubMed] [Google Scholar]
- Bender W., Akam M., Karch F., Beachy P. A., Peifer M., Spierer P., Lewis E. B., Hogness D. S. Molecular Genetics of the Bithorax Complex in Drosophila melanogaster. Science. 1983 Jul 1;221(4605):23–29. doi: 10.1126/science.221.4605.23. [DOI] [PubMed] [Google Scholar]
- Bender W., Weiffenbach B., Karch F., Peifer M. Domains of cis-interaction in the bithorax complex. Cold Spring Harb Symp Quant Biol. 1985;50:173–180. doi: 10.1101/sqb.1985.050.01.023. [DOI] [PubMed] [Google Scholar]
- Capdevila M. P., Garcia-Bellido A. Development and genetic analysis of bithorax phenocopies in Drosophila. Nature. 1974 Aug 9;250(5466):500–502. doi: 10.1038/250500a0. [DOI] [PubMed] [Google Scholar]
- Castelli-Gair J. E., Micol J. L., García-Bellido A. Transvection in the Drosophila Ultrabithorax gene: a Cbx1 mutant allele induces ectopic expression of a normal allele in trans. Genetics. 1990 Sep;126(1):177–184. doi: 10.1093/genetics/126.1.177. [DOI] [PMC free article] [PubMed] [Google Scholar]
- García-Bellido A. Genetic control of wing disc development in Drosophila. Ciba Found Symp. 1975;0(29):161–182. doi: 10.1002/9780470720110.ch8. [DOI] [PubMed] [Google Scholar]
- González-Gaitán M. A., Micol J. L., García-Bellido A. Developmental genetic analysis of Contrabithorax mutations in Drosophila melanogaster. Genetics. 1990 Sep;126(1):139–155. doi: 10.1093/genetics/126.1.139. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Hayes P. H., Sato T., Denell R. E. Homoeosis in Drosophila: the ultrabithorax larval syndrome. Proc Natl Acad Sci U S A. 1984 Jan;81(2):545–549. doi: 10.1073/pnas.81.2.545. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Hogness D. S., Lipshitz H. D., Beachy P. A., Peattie D. A., Saint R. B., Goldschmidt-Clermont M., Harte P. J., Gavis E. R., Helfand S. L. Regulation and products of the Ubx domain of the bithorax complex. Cold Spring Harb Symp Quant Biol. 1985;50:181–194. doi: 10.1101/sqb.1985.050.01.024. [DOI] [PubMed] [Google Scholar]
- Jack J. W., Judd B. H. Allelic pairing and gene regulation: A model for the zeste-white interaction in Drosophila melanogaster. Proc Natl Acad Sci U S A. 1979 Mar;76(3):1368–1372. doi: 10.1073/pnas.76.3.1368. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Lewis E. B. A gene complex controlling segmentation in Drosophila. Nature. 1978 Dec 7;276(5688):565–570. doi: 10.1038/276565a0. [DOI] [PubMed] [Google Scholar]
- Lipshitz H. D., Peattie D. A., Hogness D. S. Novel transcripts from the Ultrabithorax domain of the bithorax complex. Genes Dev. 1987 May;1(3):307–322. doi: 10.1101/gad.1.3.307. [DOI] [PubMed] [Google Scholar]
- Micol J. L., García-Bellido A. Genetic analysis of "transvection" effects involving contrabithorax mutations in Drosophila melanogaster. Proc Natl Acad Sci U S A. 1988 Feb;85(4):1146–1150. doi: 10.1073/pnas.85.4.1146. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Morata G., Sánchez-Herrero E., Casanova J. The bithorax complex of Drosophila: an overview. Cell Differ. 1986 Mar;18(2):67–78. doi: 10.1016/0045-6039(86)90001-1. [DOI] [PubMed] [Google Scholar]
- O'Connor M. B., Binari R., Perkins L. A., Bender W. Alternative RNA products from the Ultrabithorax domain of the bithorax complex. EMBO J. 1988 Feb;7(2):435–445. doi: 10.1002/j.1460-2075.1988.tb02831.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Peifer M., Bender W. The anterobithorax and bithorax mutations of the bithorax complex. EMBO J. 1986 Sep;5(9):2293–2303. doi: 10.1002/j.1460-2075.1986.tb04497.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Pirrotta V., Steller H., Bozzetti M. P. Multiple upstream regulatory elements control the expression of the Drosophila white gene. EMBO J. 1985 Dec 16;4(13A):3501–3508. doi: 10.1002/j.1460-2075.1985.tb04109.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
- White R. A., Wilcox M. Protein products of the bithorax complex in Drosophila. Cell. 1984 Nov;39(1):163–171. doi: 10.1016/0092-8674(84)90202-2. [DOI] [PubMed] [Google Scholar]
- Wu C. T., Goldberg M. L. The Drosophila zeste gene and transvection. Trends Genet. 1989 Jun;5(6):189–194. doi: 10.1016/0168-9525(89)90074-7. [DOI] [PubMed] [Google Scholar]