Polyadenylate-containing RNA in dormant and germinating <i>Botryodiplodia theobromae</i> pycnidiospores

Etten, James L. Van; Rawn, Carroll D.

doi:10.1139/m79-058

Cited by 5 publications

(2 citation statements)

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“…The amount of mRNA stored in Mucor sporangiospores is comparable to the levels found in spores of other fungi, such as Blastocladiella sp., which contained 2.5% of its RNA in the poly(A)+ form (5). The poly(A)+ RNA from Mucor spores was shown to be heterodisperse in size, ranging from 6S to 20S, a range similar to that found for stored mRNA from B. theobromae pycnidiospores (24).…”

Section: Discussionsupporting

confidence: 59%

Stored mRNA in sporangiospores of the fungus Mucor racemosus

Linz

Orlowski

1982

J Bacteriol

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When introduced into nutrient medium under air, the asexual sporangiospores of Mucor racemosus germinated within 5 to 8 h, culminating with the emergence of germ tubes. We found that sporangiospores increased 20%/o in dry weight during the first 60 min of germination, indicating a high degree of synthetic activity. Sucrose density gradient analysis of spore extracts revealed that the percentage of ribosomes associated with mRNA increased from 22.5% in dormant spores to 85% within 10 min after the addition of medium and remained at this level for at least 3 h. L-[14CJleucine was immediately incorporated at a rapid rate into protein of a leucine auxotroph, whereas [3H]uracil or [32Plphosphate was incorporated into RNA at a significant rate only 20 min after the addition of medium. This newly synthesized RNA occurred in polysomes only after 30 min had passed. Pool equilibration of the radioactive precursors was not limiting to these measurements. Polyadenylated RNA was isolated from dormant spores by oligodeoxythymidylic acid-cellulose chromatography and was found to comprise 3.3% of the total cellular RNA. Sucrose density gradient centrifugation revealed the polyadenylated RNA to be heterodisperse in size, ranging from 6S to 20S. It was concluded that M. racemosus sporangiospores contain preformed mRNA which is translated commencing immediately upon the addition of nutrient medium.

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Section: Discussionsupporting

confidence: 59%

Stored mRNA in sporangiospores of the fungus Mucor racemosus

Linz

Orlowski

1982

J Bacteriol

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“…Stable mRNA populations have been described before in the spores of a few lower eucaryotes, including Dictyostelium (3), Blastocladiella 14, Allomyces (23), Botryodiplodia (2,32), and Rhizopus (30) spp. Differential gene expression has been demonstrated during spore germination in some of these systems (5,6,24,25,31), including evidence for post-transcriptional, translational, and posttranslational regulation (6,8,10,11,15,22,24,25).…”

Section: Discussionmentioning

confidence: 86%

Differential gene expression during aerobic germination of Mucor racemosus sporangiospores

Linz

Orlowski

1984

J Bacteriol

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Evidence is provided suggesting that several modes of differential gene expression operate concomitantly during the first 60 min of germination of Mucor racemosus sporangiospores under air. Protein synthesis was initiated immediately upon exposure of the spores to nutrient medium and accelerated exponentially throughout the period of observation. All translation during the first 30 min of germination occurred using only preformed stable mRNAs as a template. Analysis of the protein products synthesized in vivo was performed by L-[35S]methionine labeling, one-and two-dimensional polyacrylamide gel electrophoresis, and autoradiography. The population of proteins accumulated during spore formation and present at the time of hlrvest differed significantly from those proteins synthesized during spore germination. Autoradiographs displayed several proteins synthesized during the former but not the latter morphogenetic process. Conversely, other proteins were synthesized during the first 30 min of germination but not during spore formation, even though the mRNA specifying these proteins must have been synthesized and stored in the dormant spore. A posttranscriptional regulatory mechanism that directs selective translation thus appears to exist in the developing spore. In addition, autoradiographs showed that many proteins, although made throughout the intervals examined, displayed significant changes in their relative rates of synthesis. One gene product exemplified a possible case of post-translational modification during the first hour of sporangiospore germination.

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