Soybean beta-conglycinin genes are clustered in several DNA regions and are regulated by transcriptional and posttranscriptional processes.

Abstract

We investigated the chromosomal organization and developmental regulation of soybean 8-conglycinin genes. The 8-conglycinin gene family contains at least 15 members divided into two major groups encoding 2.5-kilobase and 1.7-kilobase embryo mRNAs. 8-Conglycinin genes are clustered in severa1 DNA regions and are highly homologous along their entire lengths. The two groups differ by the presence or absence of specific DNA segments. These DNA segments account for the size differences in 8-conglycinin mRNAs. The 2.5-kilobase and 1.7-kilobase 8-conglycinin mRNAs accumulate and decay at different times during embryogenesis. By contrast, genes encoding these mRNAs are transcriptionally activated and repressed at the same time periods. Our studies indicate that the 8-conglycinin family evolved by both duplication and insertion/deletion events, and that 8-conglycinin gene expression is regulated at both the transcriptional and posttranscriptional levels.

Effect of short-term application of nitrogen on the accumulation of β-subunit of β-conglycinin in nitrogen-starved soybean (Glycine maxL.) developing seeds

“…The cDNA was ligated into the pT-Adv vector using the AdvanTAge™ PCR Cloning Kit (Clontec Inc., California, USA) and transformed to TOP lOF cells (Clontec Inc.). The sequence of this cDNA was completely identical with that reported by Harada et al (1989).…”

Kunitz trypsin inhibitor genes are differentially expressed during the soybean life cycle and in transformed tobacco plants.

“…The reduced organ SyStem expression levels are due in part to lower Kunitz trypsin inhibitor gene transcription rates in the leaf, root, and stem (Walling et al, 1986). Expression of the Kunitz trypsin inhibitor gene family in mature plant organ systems is similar to that observed for the lectin gene (Okamuro, Jofuku, and Goldberg, 1986;Goldberg et al, 1989), but differs from the glycinin and P-conglycinin storage protein genes that are expressed only during embryogenesis (Harada et al, 1989;Nielsen et al, 1989).…”

“…We do not know yet how all 10 Kunitz trypsin inhibitor genes are organized with respect to each other in soybean chromosomes because we have not attempted to link the genomic clones by either DNA walking studies (Harada, Barker, and Goldberg, 1989;Nielsen et al, 1989) or by genetic studies with restriction fragment length polymorphisms (Cho, Davies, and Nielsen, 1989). Analysis of individual Kunitz trypsin inhibitor genomic clones (Figure 1 B), however, demonstrated that several Kunitz trypsin inhibitor genes are linked in tandem pairs.…”

A frameshift mutation prevents Kunitz trypsin inhibitor mRNA accumulation in soybean embryos.

“…As seen in Figure 6, the hybridization patterns obtained with the KTi + and KTi~ DNAs were identical with the exception of a KTi1/2 EcoRI DNA fragment polymorphism in one KTi DNA fragments containing the KTi3 Kunitz trypsin inhibitor gene, the Le 1 lectin gene (Goldberg et al, 1983), and the CG-4 #-conglycinin gene (Barker et al, 1988;Harada et al, 1989) were fractionated by electrophoresis, transferred to nitrocellulose paper, and hybridized with 32 P-nuclear RNAs synthesized in vitro from either KTi + or KTi" midmaturation stage embryo nuclei. Hybridization conditions used are described in the legend to Soybean leaf nuclear DNAs were digested with EcoRI, fractionated by electrophoresis, transferred to nitrocellulose paper, and hybridized with a mixed probe containing plasmids A-37 and pKT3 ( Figure 1) under a reduced hybridization criterion (30°C, AT m = -30°).…”