Transcriptional Control and Pattern Formation in the Developing Vertebrate Heart: Studies on NK-2 Class Homeodomain Factors

摘要: Publisher Summary This chapter summarizes what is known about one specific gene family acting in transcriptional control and pattern formation vertebrate invertebrate hearts: the NK-2 class of homeodomain factors. It found that frog Nkx2.5 expressed a region much broader than occupied by definitive heart progenitors, resembling morphogenetic field mapped other amphibia. Thus, regulatory ability may be limited to zone expression. On hand, loss occurs advance In fish, two genes—nkx2.5 nkx2. 7—are different but overlapping domains encompassing field. nkx2.5 expression those cells definitively fated also extends more caudally beyond into will never participate development, even if progenitors are killed laser ablation. The notochord provide inhibitory signals, which keep caudal from differentiating as heart. Cells regulation have been cranial field, these express nkx2.7 not nkx2.5. findings consistent with view potency requires presence cardiac Nkx2 gene, positive negative interactions determine actual extent itself. Ectopic fish embryos, achieved microinjection mRNA fertilized eggs, leads larger hearts myocardial hyperplasia, without ectopic activation myogenic program.