Genetic control of eye development in Drosophila
The Drosophila eye is an ideal model for studying pattern formation. The adult eye develops from the
retinal primordium called eye disc. We are interested in three key events in eye development: (1) Domain specification and
growth of early eye disc, (2) Generation of photoreceptor neurons, and (3) Morphogenesis of photoreceptor structure.
- Dorsoventral patterning and growth in early eye disc
The dorsoventral (DV) boundary plays a crucial role for induction of growth and patterning of early eye disc. The
dorsal and ventral domains are specified by restricted expression of domain-specific genes. An ectopic DV boundary induces
an additional eye field whereas loss of DV boundary leads to the failure of eye development. Evidence suggests that domain
specific gene functions are regulated by antagonistic interactions of dorsal and ventral genes. We focus on analysis of
molecular genetic basis of DV gene interactions and identifying new genes involved in patterning and growth of eye primordium.
- Genetic control of early neurogenesis
After initial patterning of undifferentiated eye disc, the morphogenetic furrow is formed at the posterior margin of
the disc. Neurogenesis is initiated in the region posterior to the furrow and proceeds anteriorly as the furrow moves ahead.
The process of neurogenesis is regulated by interaction of proneural genes and anti-proneural genes. In the absence of Bar
homeobox proteins, the atonal proneural gene is ectopically induced to generate excess photoreceptors. We are analyzing
the mechanism of atonal repression by anti-proneural gene Bar.
- Cell polarity and photoreceptor morphogenesis
Photoreceptor precursors become mature photoreceptors as they form the light-sensing rhabdomere at the apical domain of
the cell. To establish this highly polarized cell structure, positional cues for apical-basal cell polarity are essential.
For instance, loss of crumbs, one of conserved polarity genes, results in disorganization of rhabdomere and apical cell
junctions. Interestingly, mutations in a human crumbs cause retinal diseases such as Retinitis Pigmentosa 12 (RP12)
and Leber Congenital Amaurosis (LCA). Thus, the understanding of polarity gene functions in organizing fly photoreceptors
will provide an insight into the molecular basis of important retinal diseases in humans.
Selected Publications
Cho K-O, Choi K-W (1998) Fringe is essential for mirror symmetry and morphogenesis in the Drosophila eye.
Nature 396:272-276.
Bhat MA, Izaddoost S, Lu Y, Cho K-O, Choi K-W, Bellen HJ (1999) Discs lost, a novel multi-PDZ domain protein,
establishes and maintains epithelial polarity. Cell 96:833-845.
Cho K-O, Chern J, Izaddoost S, Choi K-W (2000) Novel signaling from the peripodial membrane is essential for
eye disc patterning in Drosophila. Cell 103:331-342.
Izaddoost S, Nam S-C, Bhat MA, Bellen HJ, Choi K-W (2002) Drosophila Crumbs is a positional cue in
photoreceptor adherens junctions and rhabdomeres. Nature 416:178-183.
Chern JJ, Choi K-W (2002) Lobe mediates Notch signaling to control domain-specific growth in the Drosophila
eye disc. Development 129:4005-4013.
Nam SC, Choi K-W (2003) Interaction of Par-6 and Crumbs complexes is essential for photoreceptor morphogenesis
in Drosophila. Development 130:4363-4372.
Lim J, Choi K-W (2003) Bar homeodomain proteins are anti-proneural in the Drosophila eye: transcriptional
repression of atonal by Bar prevents ectopic retinal neurogenesis. Development 130:5965-5974.
Singh A, Choi K-W (2003) Initial state of the Drosophila eye before dorsoventral specification is equivalent
to ventral. Development 130:6351-6360.
Lim JH, Choi K-W (2004) Drosophila eye disc margin is a center for organizing long-range planar polarity. Genesis
39:26-37.
Lim JH, Choi K-W (2004) Induction and autoregulation of anti-proneural gene Bar during retinal neurogenesis in
Drosophila. Development 131:5573-5580.
Contact Information
- Kwang-Wook Choi, Ph.D.
- Department of Molecular and Cellular Biology
- Baylor College of Medicine
- One Baylor Plaza M820
- Houston, Texas 77030, U.S.A.
- Tel: (713) 798-8649
- Fax: (713) 798-8005
- E-mail: kchoi@bcm.tmc.edu
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