Dosage regulation of Zea mays homeobox (ZmHox) genes and their relationship with the dosage-sensitive regulatory factors of Shrunken 1 (Sh1) in maize.
1997
Guo M. | Birchler J.A.
In gene dosage studies on the expression of the maize Shrunken 1 gene, several dosage-sensitive regulatory factors were identified that modulate Sh1 mRNA levels in various aneuploids. ZmHox 1a and 1b have been shown to interact with the Sh1 promoter sequences in vitro. The present study was conducted to test whether these molecularly defined regulatory genes are subject to dosage modulation and to determine whether ZmHox 1a and 1b are involved with the dosage-sensitive modification of Sh1 expression. The result was that ZmHox 1a and 1b were effected by several trans-acting dosage modifiers and that both genes exhibited a structural gene dosage effect but did not modulate Sh1 mRNA levels. For some chromosomal regions, a correlation was found between the dosage regulation of Sh1 and that of ZmHox 1a, while other effects were not correlated. The results suggest that the dosage effects on Sh1 are not mediated by ZmHox 1a or 1b, but interestingly Sh1 and ZmHox 1a share some dosage-regulatory effects.
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