Differences in Spatial Expression between 14-3-3 Isoforms in Germinating Barley Embryos

Abstract

The family of 14-3-3 proteins is ubiquitous in eukaryotes and has been shown to exert an array of functions. We were interested in the possible role of 14-3-3 proteins in seed germination. Therefore, we studied the expression of 14-3-3 mRNA and protein in barley (Hordeum distichum L.) embryos during germination. With the use of specific cDNA probes and antibodies, we could detect individual expression of three 14-3-3 isoforms, 14-3-3A, 14-3-3B, and 14-3-3C. Each homolog was found to be expressed in barley embryos. Whereas protein levels of all three isoforms were constant during germination, mRNA expression was found to be induced upon imbibition of the grains. The induction of 14-3-3A gene expression during germination was different from that of 14-3-3B and 14-3-3C. In situ immunolocalization analysis showed similar spatial expression for 14-3-3A and 14-3-3B, while 14-3-3C expression was markedly different. Whereas 14-3-3A and 14-3-3B were expressed throughout the embryo, 14-3-3C expression was tissue specific, with the strongest expression observed in the scutellum and the L2 layer of the shoot apical meristem. These results show that 14-3-3 homologs are differently regulated in barley embryos, and provide a first step in acquiring more knowledge about the role of 14-3-3 proteins in the germination process.

Isoform-specific Subcellular Localization among 14-3-3 Proteins inArabidopsisSeems to be Driven by Client Interactions

“…The core 14-3-3 function would not be altered in this scenario, and those 14-3-3s, although diverse in sequence, would be homogenous in function. In seeming support of this notion, there is clear evidence for cell-and tissue-specific expression of 14-3-3s in both animals and plants (Daugherty et al, 1996;Testerink et al, 1999;Qiu et al, 2000;Han et al, 2001;Philip et al, 2001;Subramanian et al, 2001;Aitken, 2002;Fulgosi et al, 2002;Maraschin et al, 2003;Alsterfjord et al, 2004;van Hemert et al, 2004;Qi et al, 2005;Wijngaard et al, 2005).…”

Carbonylated proteins accumulated as vitality decreases during long-term storage of beech (Fagus sylvatica L.) seeds

“…In seeds, the 14-3-3 (Table 2) appears to be ABAdependent protein (Testerink et al 1999) involved in the stress signal transduction pathway because this protein is phosphorylated by SnRK.8, an important kinase for drought resistance (Denison et al 2011). Via interactions with phosphorylated proteins 14-3-3 modulates their function and consequently regulates transport through ion channels, virulence-mediated programmed cell death, ROS production as a defense mechanism and microtubule cell arrangement (Denison et al 2011).…”

Molecular cloning of cDNAs for 14-3-3 and its protein interactions in a white-rot fungusPhanerochaete chrysosporium

“…Based on the sequence alignment, the 14-3-3 proteins from fungi may comprise a distinct group. There are distinct spatial and temporal patterns of 14-3-3 gene expression during development in both plants (Daugherty et al, 1996;Testerink et al, 1999) and animals, particularly in the rodent brain and heart (Watanabe et al, 1993a(Watanabe et al, , 1993b(Watanabe et al, , 1994Roseboom et al, 1994;McConnell et al, 1995;Luk et al, 1998;Horie et al, 1999), suggesting that there may be isotype-specific developmental roles. However, 14-3-3 was constitutionally expressed through the experimental period in P. chrysosporium.…”