Nucleic Acids Res
February 25, 1988;
Xenopus homeobox-containing cDNAs expressed in early development.
We report the isolation of six different homeobox-containing genes in Xenopus laevis which are expressed during early embryogenesis. cDNA clones of all of them were partially sequenced including two from previously isolated Xenopus genomic loci and found to contain homeodomains which share a high degree of homology with the Antennapedia protein (50 to 59 out of 60 amino acids). We find a short region of homology (consensus Ile Tyr Pro Trp Met) in four of the cDNAs, which is also present in Antennapedia and that may correspond to a bend region preceding the homeodomain. Northern blots have been performed to show the transcriptional pattern through early frog embryogenesis. Three of the genes are expressed only during a very narrow period of embryogenesis, reinforcing the view that homeobox genes are developmentally regulated.
Nucleic Acids Res
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Figure 2: Sequence of the five Xenopus homeobox-containing gene.
A: Nucleotide sequences of all five classes of XlHbox transcripts of the
homeobox containing region. Position 1 indicates the start of the
homeobox and position 180 is the last nucleotide of the homeobox as
defined by comparison with Antp. The arrows indicate the position of
synthetic oligonucleotides used for sequencing the homeoboxes. Two
blocks of sequences identical in all five genes are highlighted.
B: Predicted translation products of nucleotide sequence in panel A.
Position 1 indicates the start of the homeo-domain and position 60 the
end. The translation stops are indicated by three stars. Amino acids
conserved in all five cDNAs are highlighted, and two long stretches of
homology are boxed.
The arrowheads in both panels indicate the predicted position of the
intron preceding the homeobox (see text).
Figure 5: Northern blot analysis of XlHbox3 (panel A), 4 (B) and 5 (C) and
actin (D) gene expression during oogenesis and embryogenesis. For staging of
oocytes and embryos see Materials and Methods. Two ug of poly-(A)+-RNA was
loaded in each track. Hybridization was done with nicktranslated insert of
each gene at high stringency (see Material and Methods). Size standards are
indicated to the left of each panel. The actin probe was a 250 bp fragmTent of
a cytoskel etal actin (clone B9.118) .
The molecular basis for metameric pattern in the Drosophila embryo.