Click here to close
Hello! We notice that you are using Internet Explorer, which is not supported by Xenbase and may cause the site to display incorrectly.
We suggest using a current version of Chrome,
FireFox, or Safari.
Biochem Biophys Res Commun
1995 Sep 14;2142:432-9.
Show Gene links
Show Anatomy links
Developmental and differential regulations in gene expression of Xenopus pleiotrophic factors-alpha and -beta.
Tsujimura A
,
Yasojima K
,
Kuboki Y
,
Suzuki A
,
Ueno N
,
Shiokawa K
,
Hashimoto-Gotoh T
.
???displayArticle.abstract???
Using conserved nucleotide sequences in mammalian osteoblast specific factor-1 (OSF-1) coding regions, we isolated two kinds of cDNA clones from the Xenopus brain library. The encoded proteins, named Xenopus pleiotrophic factors (X-PTFs)-alpha and -beta, were 65 and 87% homologous to human midkine and OSF-1, respectively. In the adult frog, X-ptf-alpha was expressed in the ovary, brain, eye, bone, heart and lung, whereas X-ptf-beta was expressed in the brain, eye and bone. By in situ hybridization of the tailbud embryo, X-ptf-alpha mRNA was detected rather broadly in the head/tail regions including the central nervous system (CNS), whereas X-ptf-beta mRNA was restricted to the CNS, particularly in the hind-brain. During embryogenesis, X-ptf-alpha mRNA was detected in the one-cell stage embryo, whereas only zygotic expression was observed in X-ptf-beta. X-ptf-beta mRNAs contained approximately 79 bp tandem repeats in the 3'-untranslated region, complementary to those found in retinoic acid cellular receptor mRNA and in the sense strand of short interspersed repeat transcripts in X. laevis.
The entire structures of representative X-ptf-alpha and X-ptf-beta cDNA clones. The cDNA structures are schematically shown with restriction-sensitive sites that were examined in all four clones. Open boxes represent the protein coding regions. Arrow-heads indicate directions and approximate positions of oligo-nt primers used for competitive RT-PCR. Shaded boxes represent tandem repeats. "poly A" indicates the presence of polyadenylation signal sequences in the cloned fragments.
Fig. 2. Similarity in the aa sequences of X-PTF-a to MK (A) and X-PTF-B to OSF-l (B). The aa sequences deduced from X-ptf-a and X-Plf-B cDNA clones isolated from a whole brain mixture from 6 adult frogs are aligned with those mammalian MK and OSF- l , respectively. Dots and dashes, respectively, represent identical and missing residues compared with those in human proteins. Asterisks indicate the positions of conserved cysteine residues. For X-PTF-a , 5 and 2 clones were ohtained,respectively, for -a1 and - a2 subtypes, within each of which, the aa sequences were identical, although the a1 clones were divided into two allelic groups by nt sequence differences (2 and 3 clones in each). For X-PTF-B, 6 and 5 clones were,respectively,obtained for the B1 and B2 subtypes. The B1 clones were divided into two allelic groups according to their nt sequences (3 in each). Two of the X-Ptf-B2 clones were identical and three contained aa substitutions as follows: Clone#1, His-24to Leu, Clone #10, Leu-10 to Met, Lys42 to Thr and Lys1 and Gly1 in human mature MK and OSF-1 proteins, respectively. The leader signal peptide sequences are shown above the human MK and OSF-1 sequences.
Fig. 3 Distribution of X-ptf-a and X-ptf-B transcripts in tailbud stage embryos. A digoxigenin-labeled cRNA probe was prepared by in vitro synthesis using SP6 RNA polymerase from the X-ptf-a or X-ptf-B coding regions on pSP64-poly(A). Whole mount in situ hybridization transcript distribution from the side. (B) and (C) X-ptf-B transcript distribution from the side and top, respectively.
Fig. 4. Competitive RT-PCR analysis of a cDNA mixture synthesized from total RNA of Xenopus embryos at various developmental stages. Total RNA was isolated, cDNA was synthesized and competitive RT-PCR was performed as described in the Materials and Methods. The number of developmental stages(12) is shown on the top of each lane. Stage "0" means unfertilized egg. Closed and open arrows indicate positions of the amplified DNAs that originated from X-ptf-a, X-ptf-B or X-ef-1 transcripts and those of each competitor DNA, respectively. The sizes of the PCR-amplifiedfragments are indicated on the right.
Fig. 5. X-ptf-a and X-ptf-B gene expression in animal cap cells incubated with active or bFGF. Animal cap explants isolated from stage 8 embryos were incubated in 50% MBS/0.1% BSA without inducing factor (control), with 10ng/ml action A or 50ng/ml bFGF for 5, 24 or 48 hours at 21 degrees Celsius. Inducing factors and incubation periods were as indicated on the top of the respective lanes. Closed and open arrows, as well as the size of the PCR-amplified fragments are as described in the legend to Fig.4.
mdk.L (midkine) gene expression in Xenopus laevis embryo, assayed via in situ hybridization, NF stage 28, lateral view, anteriorleft, dorsal up.
mdk.S (midkine) gene expression in Xenopus laevis embryo, assayed via in situ hybridization, NF stage 28, lateral view, anteriorleft, dorsal up.
