Zebrafish cellular nucleic acid-binding protein: gene structure and developmental behaviour

• Published in: Gene Vol. 337; pp. 151 - 161
• Main Authors: Armas, Pablo, Cachero, Sebastián, Lombardo, Verónica A, Weiner, Andrea, Allende, Miguel L, Calcaterra, Nora B
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 04.08.2004
• Subjects: Alternative Splicing; Amino Acid Sequence; Animals; CCHC-motif; Cloning, Molecular; Danio rerio; Developmental pattern expression; DNA, Complementary - chemistry; DNA, Complementary - genetics; Early embryogenesis; Embryo, Nonmammalian - metabolism; Embryonic Development; Female; Gene Expression Regulation, Developmental; Genes - genetics; Immunohistochemistry; In Situ Hybridization; Male; Molecular Sequence Data; Ovary - embryology; Ovary - growth & development; Ovary - metabolism; Protein Binding; Protein Isoforms - genetics; Protein Isoforms - metabolism; RNA Probes - genetics; RNA Probes - metabolism; RNA, Messenger - genetics; RNA, Messenger - metabolism; RNA-Binding Proteins - genetics; RNA-Binding Proteins - metabolism; Sequence Alignment; Sequence Analysis, DNA; Single-stranded nucleic acid-binding protein; Whole-mount immunohistochemistry; Zebrafish - embryology; Zebrafish - genetics; Zebrafish - growth & development; Zebrafish Proteins - genetics; Zebrafish Proteins - metabolism; PBS; Developmental pattern expression; Early embryogenesis; CNBP; EST; CCHC-motif; Whole-mount immunohistochemistry; EMSA; RT-PCR; RACE; Single-stranded nucleic acid-binding protein; MBT; PCR
• ISSN: 0378-1119; 1879-0038
• DOI: 10.1016/j.gene.2004.04.031

Here we analyse the structural organisation and expression of the zebrafish cellular nucleic acid-binding protein (zCNBP) gene and protein. The gene is organised in five exons and four introns. A noteworthy feature of the gene is the absence of a predicted promoter region. The coding region encodes a 163-amino acid polypeptide with the highly conserved general structural organisation of seven CCHC Zn knuckle domains and an RGG box between the first and the second Zn knuckles. Although theoretical alternative splicing is possible, only one form of zCNBP is actually detected. This form is able to bind to single-stranded DNA and RNA probes in vitro. The analysis of zCNBP developmental expression shows a high amount of CNBP–mRNA in ovary and during the first developmental stages. CNBP–mRNA levels decrease while early development progresses until the midblastula transition (MBT) stage and increases again thereafter. The protein is localised in the cytoplasm of blastomeres whereas it is mainly nuclear in developmental stages after the MBT. These findings suggest that CNBP is a strikingly conserved single-stranded nucleic acid-binding protein which might interact with maternal mRNA during its storage in the embryo cell cytoplasm. It becomes nuclear once MBT takes place possibly in order to modulate zygotic transcription and/or to associate with newly synthesised transcripts.