TABLE 1.
Fox− regulatory ORFs mutated by Tn5-1063, complementation, and predicted functions of their products
| ORF (name of gene) | No. of mutants with a Tn in that ORF | Mutant(s) studied | Chromosomal site (21) of Tn insertion (bp) | Complementing fosmid clone | Complementing replicating plasmid | Predicted function | Heterocyst envelope phenotypea |
|---|---|---|---|---|---|---|---|
| alr0117 (hepN) | 6 | FQ671 | 120135 | anc0709 | pRL2855a | Two-component sensory histidine kinase | Hgl+ Hep− |
| all0187 (conR) | 1 | FQ1062 | 201581 | anc1418 | pRL3055 | Transcriptional regulator | Hgl+ Hep+b |
| alr1086 (henR) | 11 | FQ621 | 1272510 | anc3515 | pRL3194 | Two-component response regulator | Hgl− Hep− (has fibrous layer) |
| all2760 (hepS) | 6 | FQ1487, FQ1641 | 3356965, 3357475 | anc1982 | pRL2858a | Serine/threonine kinase | Hgl+ Hep− |
| alr5348 | 3 | FQ1281 (11) | —c | — | — | Bears Spo0J-like domain | Hgl+ (11) Hep− |
a
Within the context of this study, Hgl+ and Hgl− phenotypes are, respectively, those in which heterocysts bear or do not bear a laminated layer of envelope glycolipids. More generally, an Hgl mutant can be one in which heterocyst envelope glycolipids are not synthesized (11) or are synthesized but not deposited in an organized array, as in an hglK mutant (2). Hep+, heterocysts bear a homogeneous envelope layer of compacted polysaccharide; Hep−, they bear no such layer.
b
In FQ1062, polar junctions of heterocysts to vegetative cells are usually abnormally little constricted.
c
—, see reference 11.