Reference "Comparative analysis of BiP gene expression in maize endosperm"

Reference ID

7114

Title

Comparative analysis of BiP gene expression in maize endosperm

Source

Gene, 1997, vol. 204, pp. 105-113

Authors (3)

Wrobel-R-L	OBrian-G-R
Boston-R-S

Abstract

Binding protein (BiP) is the endoplasmic reticulum member of the highly
conserved HSP70 (heat shock protein 70) family of molecular chaperones. We have
isolated and characterized two different BiP cDNA clones corresponding to genes
expressed in immature kernels. These two cDNAs share extensive sequence
similarity but map to unlinked loci in the maize genome. A comparison of the aa
sequences predicted from the cDNA clones revealed only six aa differences
between them. Investigation of gene-specific expression was carried out by RNA
gel blot analysis. RNAs corresponding to both cDNA clones were present in
increased amounts in the endosperm of floury-2 (fl2), Mucronate (Mc) and
Defective endosperm-B30 (De*-B30) maize mutants, which produce abnormal storage
proteins. Similar increases in RNAs corresponding to both probes were detected
in cells treated with either of two agents that interfere with protein folding,
azetidine-2-carboxylic acid (AZC) and tunicamycin. Investigation of the genomic
complexity of the BiP genes by Southern blot analysis revealed several cross-
hybridizing bands. These results are suggestive that the BiP genes expressed in
endosperm are coordinately regulated members of a more complex maize BiP
multigene family.