The long-term objective of this project is to obtain an understanding of how an elaborate developmental process is accomplished by the integrated expression of a large number of genes. Failure to integrate the expression of various structural genes is the basis for a variety of human developmental defects. The model system chosen for this study is the production of the chorion (eggshell) by the monolayer of follicle cells surrounding the maturing oocyte of the silkmoth, Bombyx mori. In these cells the synthesis of over 100 chorion proteins follows a precise temporal pattern corresponding to a program of specific mRNA production. One useful property of this system is that all chorion genes are tightly clustered on a small segment of one chromosome. The size of this region is estimated to be 700 kilobases. Recovery of the entire locus on recombinant clones (500 kb of which is already accomplished) along with detailed characterizations of the genes encountered, will provide a rare opportunity to trace the evolution of a complex developmental process, as well as provide the groundwork for studies designed to understand how the locus is coordinately regulated. Our study of gene regulation will involve two major approaches. First, utilizing the synchronous populations of cells that can be dissected from the silkmoth ovary, we will examine the structural changes of the chorion genes within the nucleus prior to and during their expression. These structural changes will be monitored by determining the accessibility of the genes to DNase I digestions. Such experiments address the important question of how genes are marked in the nucleus for subsequent expression. Second, we will determine whether the chorion locus is divided into looped chromosomal domains. Evidence for such loops will be obtained by if segments of the chorion locus are found to be associated with the nuclear matrix, an elaborate protein network within the nucleus. The use of mutations containing breakage points within the chorion locus will be extremely helpful in determining the functional role of such putative attachment sites.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
5R01GM031867-06
Application #
3280285
Study Section
Genetics Study Section (GEN)
Project Start
1983-04-01
Project End
1991-11-30
Budget Start
1988-12-01
Budget End
1989-11-30
Support Year
6
Fiscal Year
1989
Total Cost
Indirect Cost
Name
University of Rochester
Department
Type
Schools of Arts and Sciences
DUNS #
208469486
City
Rochester
State
NY
Country
United States
Zip Code
14627
Nimigean, Crina M; Miller, Christopher (2002) Na+ block and permeation in a K+ channel of known structure. J Gen Physiol 120:323-35
Xiong, Y; Burke, W D; Eickbush, T H (1993) Pao, a highly divergent retrotransposable element from Bombyx mori containing long terminal repeats with tandem copies of the putative R region. Nucleic Acids Res 21:2117-23
Burke, W D; Eickbush, D G; Xiong, Y et al. (1993) Sequence relationship of retrotransposable elements R1 and R2 within and between divergent insect species. Mol Biol Evol 10:163-85
Jakubczak, J L; Burke, W D; Eickbush, T H (1991) Retrotransposable elements R1 and R2 interrupt the rRNA genes of most insects. Proc Natl Acad Sci U S A 88:3295-9
Hibner, B L; Burke, W D; Eickbush, T H (1991) Sequence identity in an early chorion multigene family is the result of localized gene conversion. Genetics 128:595-606
Jakubczak, J L; Xiong, Y; Eickbush, T H (1990) Type I (R1) and type II (R2) ribosomal DNA insertions of Drosophila melanogaster are retrotransposable elements closely related to those of Bombyx mori. J Mol Biol 212:37-52
Yue, X N; Sakaguchi, B; Eickbush, T H (1988) Gene conversions can generate sequence variants in the late chorion multigene families of Bombyx mori. Genetics 120:221-31
Xiong, Y; Burke, W D; Jakubczak, J L et al. (1988) Ribosomal DNA insertion elements R1Bm and R2Bm can transpose in a sequence specific manner to locations outside the 28S genes. Nucleic Acids Res 16:10561-73
Nur, U; Werren, J H; Eickbush, D G et al. (1988) A ""selfish"" B chromosome that enhances its transmission by eliminating the paternal genome. Science 240:512-4
Eickbush, T H; Robins, B (1985) Bombyx mori 28S ribosomal genes contain insertion elements similar to the Type I and II elements of Drosophila melanogaster. EMBO J 4:2281-5