Differential expression of fork head genes during early Xenopus and zebrafish development

Abstract

Intense efforts have been devoted to the identification of genes that are causatively involved in pattern-forming events of invertebrates and vertebrates. Several gene families involved in this process have been identified. Here we focus on the Xenopus fork head domain gene family. One of its members, XFKH1/Pintallavis/XFD1, has been shown previously to be involved in axial formation, and the expression patterns of the other family members discussed below suggest that they too play a major role in the initial steps of patterning and axial organization. In this report, we describe four Xenopus fork head genes (XFKH3, 4, 5, and 6) and analyze the distribution of their transcripts during early development. XFKH3 is expressed in developing somites but not notochord, XFKH4 in forebrain, anterior retina, and neural crest cells, and XFKH5 in a subset of epidermal cells and the neural floor plate. Finally, transcripts of XFKH6 are seen in neural crest-derived cranial ganglia. In addition, we show that at least some of the zebrafish fork head genes might serve a comparable function. Zebrafish zf-FKH1 has a similar expression pattern as Xenopus XFKH1/Pintallavis/XFD1. It is transcribed in the notochord and neural floor plate. The polster or "pillow" also shows very high levels of zf-FKH1 mRNA.

Predicted Protein Structure of MedakaFoxA3and Its Expression in Polster

“…The product of the other gene, Mefkh1, had a DNAbinding domain of the FoxA3 type. The predicted amino acid sequence of the Fox domain of the Mefkh1 product was most similar to that of the fkd2/zffkh1 product (Dirksen andJamrich, 1995, Odenthal andNüsslein-Volhard, 1998). However, the expression patterns were different in some aspects.…”

“…All class I (FoxA type proteins) genes in vertebrates are expressed in the derivatives of the embryonic shield. The fkd2/zffkh1 gene (zebrafish FoxA3) is expressed in the embryonic shield, notochord, floor plate, polster (Dirksen and Jamrich, 1995) and neural crest cells (Odenthal and Nüsslein-Volhard, 1998). On the other hand, Mefkh1 (medaka FoxA3) is expressed only in the embryonic shield and polster, and slightly in axial tissue (Fig.…”

Identification of neural crest competence territory: Role of Wnt signaling

“…Finally, we should mention that many recent experiments show the role of a number of transcription factors in neural crest induction (for a review, see Mayor and Aybar, 2001;, including Snail Essex et al, 1993;Linker et al, 2000;Aybar et al, 2003), Slug (Mayor et al, 1995), Zic5 (Nakata et al, 2000), FoxD3 (Dirksen and Jamrich, 1995;Sasai et al, 2001), Twist (Hopwood et al, 1989), Sox9 (Spokony et al, 2002), and Sox10 (Aoki et al, 2003;Honoré et al, 2003). The overexpression of these factors leads to an expansion of neural crest exactly in the region that we have identified as the neural crest competence territory.…”

Expression of FoxP2 during zebrafish development and in the adult brain

“…Several other regions of the brain also show high levels of Foxp2 expression. KEY WORDS: Emx, forkhead, FoxP2, homeobox, speech, telencephalon, zebrafish Forkhead proteins are important transcriptional regulators that are involved in pattern formation during vertebrate development as well as in tissue specific gene expression and tumorogenesis (Accili and Arden, 2004, Carlsson and Mahlapuu, 2002, Dirksen and Jamrich, 1992, Dirksen and Jamrich, 1995, El-Hodiri et al, 2001, Erickson, 2001, Kaufmann and Knochel, 1996, Lai et al, 2001, Lai et al, 1990, Lehmann et al, 2003, Li and Vogt, 1993, Tseng et al, 2004.FOXP2, a member of the Foxp subfamily of Fox genes, is the only gene shown to be involved in speech and language development in humans (Bruce and Margolis, 2002, Enard et al, 2002, Fisher et al, 1998, Katoh, 2004, Lai et al, 2001, Lu et al, 2002, Saleem et al, 2003, Shu et al, 2001, Wang et al, 2003, Zhang et al, 2002. Mutations in this gene result in impaired linguistic and grammatical skills that, together with diminished control of complex face and mouth movements, lead to disrupted speech (Hurst et al, 1990.…”

“…Forkhead proteins are important transcriptional regulators that are involved in pattern formation during vertebrate development as well as in tissue specific gene expression and tumorogenesis (Accili and Arden, 2004, Carlsson and Mahlapuu, 2002, Dirksen and Jamrich, 1992, Dirksen and Jamrich, 1995, El-Hodiri et al, 2001, Erickson, 2001, Kaufmann and Knochel, 1996, Lai et al, 2001, Lai et al, 1990, Lehmann et al, 2003, Li and Vogt, 1993, Tseng et al, 2004.…”