macho-1-Related genes in Ciona embryos.
In ascidians, maternal factor(s) localized in the myoplasm of the egg are essential for specification and subsequent differentiation of larval muscle cells. The macho-1 gene of Halocynthia roretzi encodes a zinc-finger protein: the gene is only expressed maternally, the resultant maternal mRNA is localized to the myoplasm, and the gene function is essential for muscle cell differentiation. Here we have characterized macho-1 homologues, Ci-macho1 of Ciona intestinalis and Cs-macho1 of Ciona savignyi. Interestingly, we found that the Ciona macho-1 genes are expressed both maternally and zygotically: their maternal transcript is localized to the myoplasm while their zygotic expression is seen after neurulation in cells of the central nervous system. Functional suppression of Cs-macho1 with morpholino antisense oligonucleotide resulted in inhibition of the initiation of zygotic expression of a muscle-specific actin gene. We propose a possible evolutionary scenario in which an ancestral Zic-related gene gave rise to both the macho-1-like muscle determinant gene as well as neuronal Zic genes.
Satou
Yutaka
Y
Department of Zoology, Graduate School of Science, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan. yutaka@ascidian.zool.kyoto-u.ac.jp
Yagi
Kasumi
K
Imai
Kaoru S
KS
Yamada
Lixy
L
Nishida
Hiroki
H
Satoh
Nori
N
D000595:Amino Acid Sequence; D000818:Animals; D002352:Carrier Proteins / Q000235:genetics*; D002938:Ciona intestinalis / Q000196:embryology / Q000235:genetics*; D017124:Conserved Sequence; D018076:DNA, Complementary; D004527:Egg Proteins / Q000235:genetics*; D019143:Evolution, Molecular; D047908:Intracellular Signaling Peptides and Proteins; D008969:Molecular Sequence Data; D016415:Sequence Alignment
D002352:Carrier Proteins; D018076:DNA, Complementary; D004527:Egg Proteins; D047908:Intracellular Signaling Peptides and Proteins; C420970:macho-1 protein, Halocynthia roretzi