ABSTRACT
Los miembros de los vertebrados son estructuras complejas con tres ejes a considerar, proximal-distal, anterior-posterior y dorsal-ventral. La batería de genes involucrados en la formación de estas estructuras está bastante conservada en la evolución. El esbozo del miembro está compuesto de células mesenquimáticas indiferenciadas que derivan del mesodermo lateral somático cubiertas por ectodermo. La cresta apical ectodérmica es un centro productor de señales para el desarrollo y se ubica en el margen distal del esbozo de miembro. La zona de progreso esta a continuación y permite el crecimiento del miembro. El tipo de estructuras formadas a lo largo del eje proximal distal es especificado por los genes Hox. La proteína Sonic Hedgehog está involucrada en la regulación de la actividad de un segundo centro de señales conocido como zona de actividad polarizante. Los miembros también tienen una polaridad dorso ventral. La proteína WNT7A secretada desde el ectodermo dorsal, instruye a las células mesenquimales circundantes a diferenciarse en estructuras dorsales mientras que Engrailed 1 expresado en el ectodermo ventral, inhibe la expresión de WNT7A en esta zona del esbozo de miembro promoviendo la formación de estructuras ventrales.
Members of vertebrates are complex structures with three lines to consider, proximal-distal, anterior-posterior and dorsal-ventral. The battery of genes involved in the formation of these structures is well conserved in evolution. The outline of the member is composed of undifferentiated mesenchymal cells derived from somatic lateral mesoderm covered by ectoderm. The apical ectodermal ridge is a signal producing center for development and is located in the distal margin of the outline of a member. The area of progress is below and allows the growth of the member. The type of structures formed along the proximal distal axis is specified by Hox genes. Sonic Hedgehog protein is involved in regulating the activity of a second signaling center known as the zone of polarizing activity. Members also have a dorsal ventral polarity. The Wnt protein secreted from the dorsal ectoderm, instructs the surrounding mesenchymal cells to differentiate into dorsal structures whereas Engrailed 1 expressed in the ventral ectoderm, inhibit the expression of WNT7A outline in this membership area promoting the formation of ventral structures.
Subject(s)
Animals , Vertebrates/growth & development , Extremities/growth & developmentABSTRACT
Protein kinase CK1 is a ser/thr protein kinase family which has been identified in the cytosol cell fraction, associated with membranes as well as in the nucleus. Several isoforms of this gene family have been described in various organisms: CK1 , CK1á, CK1δ, CK1å and CK1γ. Over the last decade, several members of this family have been involved in development processes related to wnt and sonic hedgehog signalling pathways. However, there is no detailed temporal information on the CK1 family in embryonic stages, even though orthologous genes have been described in several different vertebrate species. In this study, we describe for the first time the cloning and detailed expression pattern of five CK1 zebrafish genes. Sequence analysis revealed that zebrafish CK1 proteins are highly homologous to other vertebrate orthologues. Zebrafish CK1 genes are expressed throughout development in common and different territories. All the genes studied in development show maternal and zygotic expression with the exception of CK1å. This last gene presents only a zygotic component of expression. In early stages of development CK1 genes are ubiquitously expressed with the exception of CK1å. In later stages the five CK1 genes are expressed in the brain but not in the same way. This observation probably implicates the CK1 family genes in different and also in redundant functions. This is the first time that a detailed comparison of the expression of CK1 family genes is directly assessed in a vertebrate system throughout development.