Roles for RA signaling during development have also been characterized in invertebrate chordates, that is, in cephalochordates and tunicates, and it has been shown that RA functions, in particular in developmental patterning, are well conserved, at least between cephalochordates and vertebrates. In the course of vertebrate development, for example, RA controls cell proliferation, cell differentiation, apoptosis, and cell survival, acting at different developmental stages, from early gastrulation to late organogenesis, and in all embryonic tissue layers. RA signaling is involved in the control of a wide range of biological processes.
Although a variety of retinoids are detectable in vertebrates, all- trans retinoic acid (RA) is the main biologically active vitamin A derivative during embryogenesis. This ‘RAR code’ might function in regionalization and patterning of these two tissues by differentially modulating the expression of downstream effector genes during development.ĭevelopmental functions of vitamin A derivatives (also called retinoids) have been described in great detail in various vertebrate species since the first half of the twentieth century.
Moreover, we describe a combinatorial code of lamprey rar expression in both anterior CNS and pharynx resulting from dynamic and highly specific expression patterns during embryonic development.
Conclusions Our results indicate that the genome of lampreys encodes at least four rar genes and suggest that the lamprey rar complement arose from vertebrate-specific whole genome duplications followed by a lamprey-specific duplication event. In particular, lamprey rar genes exhibit combinatorial expression domains in the anterior central nervous system (CNS) and the pharyngeal region. The results show that lamprey rar genes are generally characterized by dynamic and highly specific expression domains in different embryonic tissues. We further assessed their expression patterns during embryonic development by in situ hybridization. Results We identified four rar paralogs ( rar1, rar2, rar3, and rar4) in each of the three lamprey species, and phylogenetic analyses indicate a complex evolutionary history of lamprey rar genes including the origin of rar1 and rar4 by lineage-specific duplication after the lamprey-hagfish split. Here, we present the first extensive study of cyclostome RARs focusing on three different lamprey species: the European freshwater lamprey, Lampetra fluviatilis, the sea lamprey, Petromyzon marinus, and the Japanese lamprey, Lethenteron japonicum. While RARs have been extensively studied in jawed vertebrates (that is, gnathostomes) and invertebrate chordates, very little is known about the repertoire and developmental roles of RARs in cyclostomes, which are extant jawless vertebrates. The functions of RA are chiefly mediated by a subfamily of nuclear hormone receptors, the retinoic acid receptors (RARs), that act as ligand-activated transcription factors. 小林明子 – GOLDEN☆BEST 小林明子 Single Collection~恋におちて~ (2011.08.17/MP3+Flac/RAR) BLACKPINK – DDU-DU DDU-DU.īackground Retinoic acid (RA) signaling controls many developmental processes in chordates, from early axis specification to late organogenesis. Utada Hikaru Single Collection Vol.1 (2014 Remastered). 3 心を開いて 4 Change my mind 5 Don’t you see!