title: Expression of a germination-specific amidase, SleB, of Bacilli in the forespore compartment of sporulating cells and its localization on the exterior side of the cortex in dormant spores.
abstract: A germination-specific amidase of bacilli is a major spore-lytic enzyme that is synthesized with a putative signal sequence and hydrolyses spore cortex in situ. The sleB gene encoding this amidase in Bacillus subtilis and Bacillus cereus was expressed in the forespore compartment of sporulating cells under the control of sigmaG, as shown by Northern blot and primer extension analyses. The forespore-specific expression of B. subtilis sleB was further indicated by the forespore-specific accumulation of a SleB-green fluorescent protein fusion protein from which a putative secretion signal of SleB was deleted. Immunoelectron microscopy with anti-SleB antiserum and a colloidal gold-immunoglobulin G complex showed that the enzymes from both Bacillus species are located just inside the spore coat layer in the dormant spore, and in the dormant spore, the amidases appear exist in a mature form lacking a signal sequence. These results indicate that SleB is translocated across the forespore's inner membrane by a secretion signal peptide and is deposited in cortex layer synthesized between the forespore inner and outer membranes. The peripheral location of the spore-lytic enzymes in the dormant spore suggests that spore germination is initiated at the exterior of the cortex.
authors: Department of Molecular Biosciences, Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, Aichi 464-8601, Japan. moriyama@agr.nagoya-u-ac.jp
authors: R
authors: R
authors: Moriyama
authors: H
authors: H
authors: Fukuoka
authors: S
authors: S
authors: Miyata
authors: S
authors: S
authors: Kudoh
authors: A
authors: A
authors: Hattori
authors: S
authors: S
authors: Kozuka
authors: Y
authors: Y
authors: Yasuda
authors: K
authors: K
authors: Tochikubo
authors: S
authors: S
authors: Makino
mesh_terms: D000581:Amidohydrolases / Q000235:genetics / Q000302:isolation & purification*; D001407:Bacillus / Q000502:physiology*; D001409:Bacillus cereus / Q000502:physiology; D001412:Bacillus subtilis / Q000502:physiology; D001426:Bacterial Proteins; D002451:Cell Compartmentation; D049452:Green Fluorescent Proteins; D008164:Luminescent Proteins / Q000235:genetics / Q000302:isolation & purification; D008856:Microscopy, Fluorescence; D016253:Microscopy, Immunoelectron; D008954:Models, Biological; D011993:Recombinant Fusion Proteins / Q000302:isolation & purification; D013171:Spores, Bacterial / Q000502:physiology; D013997:Time Factors
chemical_list: D001426:Bacterial Proteins; D008164:Luminescent Proteins; D011993:Recombinant Fusion Proteins; C101656:SleB protein, Bacillus; D049452:Green Fluorescent Proteins; D000581:Amidohydrolases