Tetsuya Tabata

Nuclear protein(s) binding to the conserved DNA hexameric sequence postulated to regulate transcription of wheat histone genes

Nuclear protein(s) that specifically bind(s) to the upstream hexamer motif, ACGTCA, of wheat histone H3 and H4 genes has (have) been identified. Sequences homologous to this hexamer are found to be conserved in the upstream region of not only wheat histone genes but also other plant and animal histone genes. This suggests a possible role(s) for the hexamer and the nuclear protein(s) in the transcriptional regulation of the wheat histone genes. This hexamer is homologous to the upstream core sequence, TGACGTCA, which is highly conserved in some animal genes whose expression is regulated by cAMP.

Nucleotide sequence and genomic organisation of a wheat histone H3 gene

SummaryA wheat histone H3 gene was cloned and its primary structure investigated. DNA sequence analysis showed that the deduced amino acid sequence of the wheat histone H3 protein was identical to that of the pea. The H3 gene (TH012) was closely linked to one (TH011) of the H4 genes. The direction of transcription of the two genes (TH011 and TH012) was identical. The 5′ terminus of the transcript from the H3 gene was mapped on the cloned gene. Southern blotting analysis suggested that the copy number of the H3 genes was 80–100 per hexaploid wheat genome and not all of them were linked closely to the H4 genes in the wheat genome.

Multiplicity of the DNA-binding protein HBP-1 specific to the conserved hexameric sequence ACGTCA in various plant gene promoters

Multiplicity; DNA‐binding protein; Hexameric sequence; DNA‐protein interaction

DNA-binding protein(s) interacts with a conserved nonameric sequence in the upstream regions of wheat histone genes

A nuclear protein(s), HBP‐2, that binds to the upstream region of the wheat histone H4 gene was identified from a fractionated nuclear extract of wheat germ by DNase I footprinting. The DNase I‐protected region contained the conserved nonameric motif, CATCCAACG. Cross‐competition experiments that used the mobility shift assay showed that this nuclear protein(s) binds specifically to the upstream sequence that has been postulated to be a cis element of the wheat H3 gene. Our findings suggest that this DNA‐binding protein(s) may be a trans‐acting factor in the regulation of the transcription of wheat histone genes.

Molecular cloning and nucleotide sequence of a variant wheat histone H4 gene

To determine whether there is structural variation among histone H4 genes in wheat, one (TH091) of the H4 genes that had been cloned from a wheat genomic DNA library was sequenced and compared with another H4 gene (TH011) which we had described previously [Tabata et al., Nucl. Acids Res. 11 (1983) 5865-5865]. Nucleotide sequence analysis revealed that there are 17 nucleotide replacements in the protein-coding region of two H4 genes, causing only one amino acid substitution: a glycine at position 4 (from the N terminus) in TH011 was replaced by an aspartic acid in TH091. S1 mapping, using total nuclear RNA from germinated seeds, indicated that the H4 gene was transcribed in vivo.

Function of the hexameric sequence in the cauliflower mosaic virus 35S RNA promoter region

The hexameric sequence ACGTCA functions in transcriptional regulation of wheat histone genes. The cauliflower mosaic virus (CaMV) 35S RNA promoter has the same hexameric sequence, and mutation analyses confirmed that the hexamer contributed greatly to transcription from the 35S promoter when a test gene with this promoter was introduced into sunflower cells. Electrophoretic mobility shift assays revealed the existence of a nuclear protein(s) in sunflower cells which is homologous to the HBP-1b that has been identified as binding to the 35S promoter in wheat. These results provide evidence of the involvement of the hexameric sequence and the HBP-1b-like DNA binding protein(s) in transcription from the 35S promoter.

Parturition in six renal allograft recipients.

Between 1983 and 1994, we studied renal function and neonatal conditions for eight pregnancies and births to six women who had received renal transplants in order to assess the effect of an allograft on pregnancy and its outcome. The gestation period was 34 to 39 weeks (mean 36 weeks and 4 days), and four pregnancies ended before term. All eight babies were delivered by cesarean section. Intrauterine growth retardation (IUGR) was found in both babies of one woman who had been treated with conventional (without cyclosporin) immunosuppression. The serum creatinine level did not change during gestation in any of the women but was elevated after delivery in four. Four mothers suffered from proteinuria (25–364 mg/dl) during gestation, but the proteinuria disappeared after delivery in all but one case. The one exception, persistent proteinuria of 100–200 mg/dl, was assumed to result from the recurrence of the original renal disease (IgA nephropathy). The reduction of creatinine clearance and hydronephrosis of one graft noted during gestation were later reversed. None of the eight babies (four females and four males) was congenitally malformed, and their Apgar scores were 6 to 9 (median 8). They are now 3 months to 11 years old, and seven of them are healthy and show good growth. One of the two IUGR babies has not grown well; her weight and height are more than 1 SD below the mean for her age, and she is mentally retarded and suffers from muscle weakness. Compared with dialysis patients, female renal allograft recipients have a better quality of life because they can safely deliver a child if they observe the criteria for pregnancy established for renal allograft recipients.