The homeobox gene<i>Xbh1</i>cooperates with proneural genes to specify ganglion cell fate within the<i>Xenopus</i>neural retina

Poggi, Lucia; Vottari, T.; Barsacchi, Giuseppina; Wittbrodt, Joachim; Vignali, Robert

doi:10.1242/dev.01099

Cited by 25 publications

(22 citation statements)

References 55 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In fly, the barH genes are expressed in the developing nervous system, act as pre-patterning genes and are involved in preventing ectopic retinal neurogenesis (Higashijima et al, 1992;Kojima et al, 2000;Lim and Choi, 2003;Sato et al, 1999). Vertebrate homologs of the barH genes have been isolated and their function examined during retina and ear development (Li et al, 2002;Mo et al, 2004;Poggi et al, 2004). In the vertebrate eye, Barhl2 function appears highly variable depending on the species.…”

Section: Targeted Disruption Of Effectors Molecules Of the Apoptotic mentioning

confidence: 99%

“…In the vertebrate eye, Barhl2 function appears highly variable depending on the species. In the mouse retina it helps specify glycinergic amacrine cells from retinal progenitors (Mo et al, 2004); and in the Xenopus retina, it promotes ganglion cell fate, downstream of the atonal genes Xath3 and Xath5 (Poggi et al, 2004). We have isolated the Xenopus and mouse Barhl2 genes, and studied their functions in Xenopus neurodevelopment.…”

Section: Targeted Disruption Of Effectors Molecules Of the Apoptotic mentioning

confidence: 99%

“…Mouse Barhl2 (Mo et al, 2004), mouse Barhl1 (Bulfone et al, 2000;Li et al, 2002) and XBarhl2 (Patterson et al, 2000;Poggi et al, 2004) sequences were determined by us. Human Barhl2 (GenBank AL355867) and human Barhl1 (GenBank AL354735) sequences were predicted from their genomic DNA sequences; rat Barhl2 (MBH1) (Saba et al, 2003;Saito et al, 1998 mostly used mouse Barhl2 for further experiments.…”

Section: Manipulation Of the Level Of Xbarhl2 Expression Interferes Wmentioning

confidence: 99%

See 2 more Smart Citations

The pro-apoptotic activity of a vertebrate Bar-like homeobox gene plays a key role in patterning theXenopusneural plate by limiting the number ofchordin- andshh-expressing cells

et al. 2005

View full text Add to dashboard Cite

Targeted disruption of effectors molecules of the apoptotic pathway have demonstrated the occurrence and magnitude of early programmed cell death(EPCD), a form of apoptosis that affects proliferating and newly differentiated cells in vertebrates, and most dramatically cells of the central nervous system (CNS). Little is known about the molecular pathways controlling apoptosis at these early developmental stages, as the roles of EPCD during patterning of the developing nervous system. We describe a new function, in Xenopus neurodevelopment, for a highly conserved homeodomain protein Barhl2. Barhl2 promotes apoptosis in the Xenopusneuroectoderm and mesoderm, acting as a transcriptional repressor, through a mechanism that cannot be attributed to an unspecific cellular stress response. We show that the pro-apoptotic activity of Barhl2 is essential during normal neural plate formation as it limits the number of chordin- and Xshh-expressing cells in the prospective notochord and floorplate,which act as organizing centers. Our findings show that Barhl2 is part of a pathway regulating EPCD. They also provide evidence that apoptosis plays an important role in regulating the size of organizing centers.

show abstract

Section: Targeted Disruption Of Effectors Molecules Of the Apoptotic mentioning

confidence: 99%

Section: Targeted Disruption Of Effectors Molecules Of the Apoptotic mentioning

confidence: 99%

Section: Manipulation Of the Level Of Xbarhl2 Expression Interferes Wmentioning

confidence: 99%

See 1 more Smart Citation

The pro-apoptotic activity of a vertebrate Bar-like homeobox gene plays a key role in patterning theXenopusneural plate by limiting the number ofchordin- andshh-expressing cells

et al. 2005

View full text Add to dashboard Cite

show abstract

“…Bar class homeodomain proteins are evolutionarily conserved and have been implicated in cell-fate specification and neuronal differentiation in Drosophila as well as other species (Higashijima et al, 1992;Jones et al, 1997;Saito et al, 1998;Bulfone et al, 2000;Patterson et al, 2000;Lim and Choi, 2003;Saba et al, 2003;Mo et al, 2004;Poggi et al, 2004). A pair of redundant Drosophila Bar proteins encoded by two adjacent genes BarH1 and BarH2 (hereafter 'Bar' for both) are specifically expressed in the nuclei of R1/6 photoreceptor neurons and are required for their differentiation (Fig.…”

Section: Introductionmentioning

confidence: 99%

Induction and autoregulation of the anti-proneural geneBarduring retinal neurogenesis inDrosophila

Lim

Choi

2004

Development

View full text Add to dashboard Cite

Neurogenesis in Drosophila eye imaginal disc is controlled by interactions of positive and negative regulatory genes. The basic helix-loop-helix (bHLH) transcription factor Atonal (Ato) plays an essential proneural function in the morphogenetic furrow to induce the formation of R8 founder neurons. Bar homeodomain proteins are required for transcriptional repression of ato in the basal undifferentiated retinal precursor cells to prevent ectopic neurogenesis posterior to the furrow of the eye disc. Thus, precise regulation of Bar expression in the basal undifferentiated cells is crucial for neural patterning in the eye. We show evidence that Bar expression in the basal undifferentiated cells is regulated by at least three different pathways, depending on the developmental time and the position in the eye disc. First, at the time of furrow initiation, Bar expression is induced independent of Ato by Hedgehog (Hh) signaling from the posterior margin of the disc. Second, during furrow progression, Bar expression is also induced by Ato-dependent EGFR (epidermal growth factor receptor) signaling from the migrating furrow. Finally, once initiated, Bar expression can be maintained by positive autoregulation. Therefore, we propose that the domain of Bar expression for Ato repression is established and maintained by a combination of non autonomous Hh/EGFR signaling pathways and autoregulation of Bar.

show abstract

“…The vertebrate Barhl1 and Barhl2 genes similarly display overlapping yet distinct patterns of expression in the CNS and sensory organs, thereby also playing redundant as well as distinct roles during neurogenesis (4, 7, 18-20, 24, 26-29, 31, 32, 34). For instance, Xenopus Barhl2 is expressed in the developing neural plate and retina during Xenopus embryogenesis and plays a key role in patterning the neural plate and specifying retinal ganglion cells (27,29).…”

mentioning

confidence: 99%

Barhl1 Regulatory Sequences Required for Cell-Specific Gene Expression and Autoregulation in the Inner Ear and Central Nervous System

Chellappa¹,

Li²,

Pauley

et al. 2008

Molecular and Cellular Biology

View full text Add to dashboard Cite

The development of the nervous system requires the concerted actions of multiple transcription factors, yet the molecular events leading to their expression remain poorly understood. Barhl1, a mammalian homeodomain transcription factor of the BarH class, is expressed by developing inner ear hair cells, cerebellar granule cells, precerebellar neurons, and collicular neurons. Targeted gene inactivation has demonstrated a crucial role for Barhl1 in the survival and/or migration of these sensory cells and neurons. Here we report the regulatory sequences of Barhl1 necessary for directing its proper spatiotemporal expression pattern in the inner ear and central nervous system (CNS). Using a transgenic approach, we have found that high-level and cell-specific expression of Barhl1 within the inner ear and CNS depends on both its 5 promoter and 3 enhancer sequences. Further transcriptional, binding, and mutational analyses of the 5 promoter have identified two homeoprotein binding motifs that can be occupied and activated by Barhl1. Moreover, proper Barhl1 expression in inner ear hair cells and cerebellar and precerebellar neurons requires the presence of Atoh1. Together, these data delineate useful Barhl1 regulatory sequences that direct strong and specific gene expression to inner ear hair cells and CNS sensory neurons, establish a role for autoregulation in the maintenance of Barhl1 expression, and identify Atoh1 as a key upstream regulator.The mammalian Barhl1 and Barhl2 proteins belong to the BarH class of homeodomain transcription factors that are evolutionarily conserved in both invertebrate and vertebrate species ranging from Drosophila flies to humans. The factors of this class are usually expressed in the developing and adult nervous systems and are required for proper neural development and survival (4, 7, 12, 13, 15, 18-20, 24, 26-32, 34). In Drosophila, BarH1 and BarH2 are coexpressed in cells of the central nervous system (CNS) and the peripheral nervous system and are redundantly required for determining the subtypes of external sensory organs and photoreceptor and primary pigment cells during eye development (12,13,15). The vertebrate Barhl1 and Barhl2 genes similarly display overlapping yet distinct patterns of expression in the CNS and sensory organs, thereby also playing redundant as well as distinct roles during neurogenesis (4, 7, 18-20, 24, 26-29, 31, 32, 34). For instance, Xenopus Barhl2 is expressed in the developing neural plate and retina during Xenopus embryogenesis and plays a key role in patterning the neural plate and specifying retinal ganglion cells (27,29).The functions of mammalian Barhl genes during murine neurogenesis have been extensively investigated previously. In the developing mouse inner ear, Barhl1 but not Barhl2 is specifically expressed in all hair cells of the cochlear and vestibular systems (4, 18). The targeted disruption of Barhl1 leads to hearing loss as a result of the age-related progressive degeneration of inner and outer hair cells in the organ of Corti (18), demonstr...

show abstract

The homeobox geneXbh1cooperates with proneural genes to specify ganglion cell fate within theXenopusneural retina

Cited by 25 publications

References 55 publications

The pro-apoptotic activity of a vertebrate Bar-like homeobox gene plays a key role in patterning theXenopusneural plate by limiting the number ofchordin- andshh-expressing cells

The pro-apoptotic activity of a vertebrate Bar-like homeobox gene plays a key role in patterning theXenopusneural plate by limiting the number ofchordin- andshh-expressing cells

Induction and autoregulation of the anti-proneural geneBarduring retinal neurogenesis inDrosophila

Barhl1 Regulatory Sequences Required for Cell-Specific Gene Expression and Autoregulation in the Inner Ear and Central Nervous System

Contact Info

Product

Resources

About