PAHB1 is an evolutionary conserved HD-GL2 homeobox gene expressed in the protoderm during Norway spruce embryo development
Article first published online: 6 AUG 2001
Copyright © 2001 Wiley-Liss, Inc.
Volume 30, Issue 4, pages 220–230, August 2001
How to Cite
Ingouff, M., Farbos, I., Lagercrantz, U. and von Arnold, S. (2001), PAHB1 is an evolutionary conserved HD-GL2 homeobox gene expressed in the protoderm during Norway spruce embryo development. Genesis, 30: 220–230. doi: 10.1002/gene.1068
- Issue published online: 6 AUG 2001
- Article first published online: 6 AUG 2001
- Manuscript Accepted: 31 MAY 2001
- Manuscript Received: 3 APR 2001
- Troedsson foundation
- Swedish Natural Science Research council.
- Picea abies;
- evolution of seed plants
Summary: In angiosperms, the protoderm or outer cell layer is the first tissue to differentiate in the embryo proper. In gymnosperms, it is not known whether a protoderm is defined and similarly differentiated. Here, we report a cDNA designated PaHB1 (for Picea abies Homeobox1), which is expressed during somatic embryogenesis in Norway spruce. PaHB1 exon/intron organization and its corresponding protein are highly similar to those of the HD-GL2 angiosperm counterparts. A phylogenetic analysis reveals that PaHB1 is strongly associated with one subclass consisting of protoderm/epiderm-specific genes. Moreover, PaHB1 expression switches from a ubiquitous expression in proembryogenic masses to an outer cell layer-specific localization during somatic embryo development. Ectopic expression of PaHB1 in somatic embryos leads to an early developmental block. The transformed embryos lack a smooth surface. These findings show that the PaHB1 expression pattern is highly analogous to angiosperm HD-GL2 homologues, suggesting similarities in the definition of the outer cell layer in seed plants. genesis 30:220–230, 2001. © 2001 Wiley-Liss, Inc.