GNC and CGA1 transcript levels were also shown to be suppressed by GA signaling through the activity of DELLA proteins and PIF3. Furthermore, GNC and CGA1 expression is altered in GA signaling and pif mutants, which could partially explain the differences in chlorophyll observed in these lines. In addition to changes in chlorophyll biosynthesis, transgenic alterations GNC and CGA1 expression were shown to influence germination, expansion growth and flowering time. This further suggests that GNC and CGA1 play an important role in maintaining the balance between GA and cytokinin signaling. In this work, we provide evidence for regulation of the chloroplast localized GLUTAMATE SYNTHASE by both GNC and CGA1, as well as confirm their role in modulating the expression of genes involved in chlorophyll biosynthesis, including HEMA1, GUN4 PORB and PORC. We demonstrate that changing the expression of GNC or CGA1 leads to changes in chloroplast development, modulating not only chlorophyll content, but also chloroplast number and total leaf starch. Like Richter et al., CGA1 expression was found to have a significant influence over the timing of important developmental events including germination, flowering time and senescence, which indicates an additional role in modulating crosstalk between cytokinin and gibberellin signaling. However, we did not observe significant differences in the timing of these developmental events with altered GNC expression. Despite this evidence of partial divergence, our results support the theory that both GNC and CGA1 integrate signals from light, nitrogen, cytokinin, and GA in order to modulate nitrogen BAY 43-9006 Raf inhibitor assimilation and chloroplast development in a partially redundant fashion. To investigate this further, we created a gnc/gin2 double mutant. The SALK_01778-gnc mutant was backcrossed into the Wt-Ler ecotype for five generations in order to produce a gnc-Ler mutant. As in Columbia, the only obvious phenotype in the gnc-Ler mutant was reduced chlorophyll content. Reciprocal crosses between gin2 and gnc-Ler produced gin2/gnc double mutants. Progeny of stable AZ 960 side effects homozygous gin2/gnc plants were plated on 6% glucose. The gnc/ gin2 double mutants exhibited similar insensitive growth characteristics to gin2 single mutants on high glucose media. In contrast, wild type and gnc mutant plants exhibited similar sugar sensitive responses and demonstrated inhibition of both cotyledon expansion and greening. Chlorophyll was extracted from 3 week old plants by using the standard acetone based extraction technique that controls for biomass as well as measured nondestructively with the Minolta SPAD-501 meter. Plants homozygous for the gnc mutation exhibit decreased chlorophyll content, removing the dark green phenotype present in the gin2 line.