Expression of p27BBP/eIF6 is highly modulated during Xenopus laevis embryogenesis

• Published in: Molecular reproduction and development 2006-04, Vol.73 (4), p.482-490
• Main Authors: Vaccaro, Maria Carmela, Cuccaro, Marta, Marco, Nadia De, Campanella, Chiara
• Format: Article
• Language: English
• Subjects: Amino Acid Sequence; Animals; Biological and medical sciences; brain; Carrier Proteins - biosynthesis; Carrier Proteins - genetics; Carrier Proteins - metabolism; Cell Proliferation; Embryo, Nonmammalian - metabolism; Embryology: invertebrates and vertebrates. Teratology; embryonic development; eyes; Female; Fundamental and applied biological sciences. Psychology; Gene Expression Regulation, Developmental - physiology; General aspects; General aspects. Development. Fetal membranes; Genetic Markers; Intermediate Filament Proteins - biosynthesis; Intermediate Filament Proteins - genetics; Intermediate Filament Proteins - metabolism; Male; mid-hindbrain transition; Molecular Sequence Data; Sequence Alignment; serine phosphorylation; somites; Xenopus laevis - embryology; Xenopus Proteins - biosynthesis; Xenopus Proteins - genetics; Xenopus Proteins - metabolism
• ISSN: 1040-452X; 1098-2795
• DOI: 10.1002/mrd.20449

Protein p27BBP/eIF6 is necessary for ribosomal function of all cells. Previous data showed that from mammals to yeast p27BBP/eIF6 is involved in the biogenesis of ribosomal subunit 60S and its association with the 60S prevents premature 80S formation regulated by PKC signaling, indicating that phosphorylation of p27BBP/eIF6 is needed for translation to occur. While in vitro p27BBP/eIF6 is constitutively expressed, and it has a high level of expression in cycling cells, in vivo its expression varies according to tissues and appears regulated by factors up to now unknown. p27BBP/eIF6 has never been investigated in developing organisms where its upregulation can be correlated with tissue growth and differentiation. In this study we have sequenced p27BBP/eIF6 cDNA and studied its expression during development of Xenopus laevis, as the first step for studying its regulation. The amino acid sequence is highly conserved with two putative PKC phosphorylation sites in serine, one site being typical of Xenopus. At the end of gastrulation, the p27BBP/eIF6 riboprobe localizes in the neural plate and in the paraxial mesoderm. In particular, from stage 24, a clear‐cut localization occurs in the perspective head. In embryos exposed to teratogens, the localization of p27BBP/eIF6 riboprobe varies according to the change of head size caused by the treatment. p27BBP/eIF6 expression is particularly evident in differentiating olfactory pits, the lens, otic vesicles, and in branchial arches. Features of particular interest are p27BBP/eIF6 high level of expression in the eye field, and in the mid‐hindbrain‐boundary, two regions with high proliferative activity. Altogether, data indicate that a modulated expression of p27BBP/eIF6 occurs in developing anlagens in addition to a basal level of expression, and may suggest a correlation between p27BBP/eIF6 and proliferative activity. Moreover, the X. laevis cDNA isolation and characterization offer new hints for further studies in relation to potential p27BBP/eIF6 phosphorylation. Mol. Reprod. Dev. © 2006 Wiley‐Liss, Inc.