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Novel Secretion Apparatus Maintains Spore Integrity and Developmental Gene Expression in Bacillus subtilis
Orientador(es)
Resumo(s)
Sporulation in Bacillus subtilis involves two cells that follow separate but
coordinately regulated developmental programs. Late in sporulation, the
developing spore (the forespore) resides within a mother cell. The regulation of
the forespore transcription factor sigma(G) that acts at this stage has remained
enigmatic. sigma(G) activity requires eight mother-cell proteins encoded in the
spoIIIA operon and the forespore protein SpoIIQ. Several of the SpoIIIA proteins
share similarity with components of specialized secretion systems. One of them
resembles a secretion ATPase and we demonstrate that the ATPase motifs are
required for sigma(G) activity. We further show that the SpoIIIA proteins and
SpoIIQ reside in a multimeric complex that spans the two membranes surrounding
the forespore. Finally, we have discovered that these proteins are all required
to maintain forespore integrity. In their absence, the forespore develops large
invaginations and collapses. Importantly, maintenance of forespore integrity
does not require sigma(G). These results support a model in which the SpoIIIA-
SpoIIQ proteins form a novel secretion apparatus that allows the mother cell to
nurture the forespore, thereby maintaining forespore physiology and sigma(G)
activity during spore maturation.
Descrição
Plos Genetics, 5(7): ARTe1000566
Palavras-chave
BACTERIAL ENDOSPORE FORMATION SPORULATION MEMBRANE-PROTEIN TRANSCRIPTION FACTOR SUBCELLULAR-LOCALIZATION SIGMA-FACTORS ENGULFMENT FORESPORE CELL LOCUS MECHANISM
Contexto Educativo
Citação
Editora
Public Library of Science (PLoS)