The orderly production of meristems with specific fates is crucial for the proper elaboration of plant architecture. meristem. in which plants are produced directly by the apical and lateral meristems (Hempel and Feldman 1994), there are at least two distinct inflorescence branching actions in maize before the spikelet meristem terminates in the production of two florets. These extra branching actions allow for greater morphological diversity among the grasses. A number of mutants have been described in maize that result in an extra number of florets within the spikelet (Veit et al. 1993). In the mutants, extra florets are initiated in male tassel spikelets (Kempton 1934), although a more extreme transformation is seen in female spikelets of the ear in which florets are transformed into long indeterminate branches (Veit et al. 1993). Studies of the mutation revealed that the spikelet meristem undergoes a delay in acquiring determinacy, allowing it to initiate florets for a longer period of time (Irish et al. 1994). The analysis of mutants led to a model (Irish 1997) in which the inflorescence meristem and its branch derivatives pass through an orderly, defined series of determinate developmental states, ending with the conversion of the terminal spikelet meristem into the upper floret. Similar branching mutants have also been described in other grass species and 1235481-90-9 supplier include the mutation of barley (Bossinger et al. 1992) and the dominant mutant of oats (Ougham et al. 1996). An abundance of genetic and molecular studies have 1235481-90-9 supplier identified several genes important for floral development. One such gene, the (has several functions in flower, seed, and ovule development (Kunst et al. 1989; Jofuku et al. 1994; Modrusan et al. 1994). In addition to its role in determining floral organ identity, affects the regulation of floral meristem identity. For example, double mutants of the poor allele with floral meristem identity mutants such as or produce more coflorescence side branches in the place of plants (Bowman et al. 1993). Also, poor alleles under short days cause the formation of tertiary floral shoots in the axils of transformed sepals (Schultz and Haughn 1993). The gene belongs to Rabbit polyclonal to PDCL a large gene family, 12 of which have been identified in (Okamuro et al. 1997). Numerous homologs have been identified in both monocots and dicots (Jofuku et al. 1994; Ohme-Takagi and Shinshi 1995; Moose and Sisco 1997). Mutations in the are defective in ovule development (Elliot et al. 1996; Klucher et al. 1996). The gene of maize has recently been shown to be an (mutants have an indeterminate spikelet in which several florets are produced instead of the two found in wild-type maize. expression was observed in a variety of lateral organs as well as the spikelet pair and spikelet meristems. Our analysis indicates that this gene is critical for the regulation of spikelet meristem determinacy in maize. Results Isolation of the ids1 gene The gene from was used to screen two maize cDNA libraries at low stringency, one prepared from immature ears and the other from vegetative meristems. The same class of cDNA was isolated from each library. The longest clone of this class was 1967 nucleotides and contained an ORF of 433 amino acids (Fig. ?(Fig.1)1) with several domains showing striking amino acid similarity to the gene of (Jofuku et al. 1994). Two tandemly repeated 68 amino acid motifs were found that share 86% amino acid identity with the domain name of the AP2 protein. The gene family can be classified into two groups, designated as EREBP-like or AP2-like, based on whether they have a couple of from the AP2 repeats, respectively (Okamuro et al. 1997). The IDS1 proteins is one of the second option course which includes the AP2, AINTEGUMENTA, Shiny15, and RAP2.7 proteins (Fig. ?(Fig.2)2) (Jofuku et al. 1994; Klucher et al. 1996; Sisco and Moose 1997; Okamuro et al. 1997). The cigarette ERE-BP proteins, that 1235481-90-9 supplier have only one of the repeats, bind DNA (Ohme-Takagi and Shinshi 1995). Therefore, by analogy chances are that IDS1 features like a transcription element. To get this, a brief stretch of fundamental amino acids that could work as a nuclear localization website is present within the IDS proteins between animo acids 100 and 110 (Fig. ?(Fig.1).1). The AP2 proteins from consists of a serine-rich acidic website in the amino terminus that could work as 1235481-90-9 supplier an activation website (Jofuku et al. 1994). Although an identical region.