Ta. Black et al., SPATIAL EXPRESSION AND AUTOREGULATION OF HETR, A GENE INVOLVED IN THECONTROL OF HETEROCYST DEVELOPMENT IN ANABAENA, Molecular microbiology, 9(1), 1993, pp. 77-84
The spatially patterned differentiation of heterocysts in the filament
ous cyanobacterium Anabaena requires a functional hetR gene. Transcrip
tional fusions to luxAB show that hetR is transcribed at a low level t
hroughout the filament when Anabaena is grown with combined nitrogen,
and that induction of the gene begins within 2 h following nitrogen de
privation. By 3.5 h, induction is localized to spaced foci. By 6 h, th
ere is an overall induction of at least threefold in whole cultures, r
eflecting at least a 20-fold increase within spatially separated cells
. The induction requires the presence of a functional hetR gene, indic
ating that hetR is autoregulatory. Full induction of a heterocyst stru
ctural gene, hepA also requires a functional hetR locus.