Abstract
A slightly modified technique of Miller was applied to nuclei isolated from roots of germinating corn embryos. Under the conditions used, the extranucleolar chromatin was easily spread but the nucleolar chromatin often remained aggregated. The nontranscribed chromatin regions consisted of long deoxyribonucleoprotein (DNP) fibrils with the typical "beads-on-a-string" appearance of nucleosomal arrangement. When the EDTA concentration of the spreading medium was increased, linear arrangement of nucleosomes, 20 nm and 40-50 nm DNP granules were observed on the same DNP fibril. The supranucleosomal granules were also closely packed without any apparent order. Independently of the EDTA concentration, numerous non-nucleolar ribonucleoprotein (RNP) fibrils with a knobby structure were seen laterally bound to DNP fibrils. These knobby RNP fibrils (transcripts) were highly folded and appeared in "bunch-of-grapes" configurations. Each RNP knob measured 23 nm in diameter and the longest of these RNP fibrils were estimated to reach 1.5 micron. The RNP fibrils were often solitary and never exceeded 8 per 10 micron of the DNP axis. Distribution, morphology, and size of these transcripts distinguished them from the nucleolar "Christmas-tree"-like figures, which were rarely observed with our material. These non-nucleolar transcriptional units may correspond to genes coding for the heterodisperse nuclear RNA (hnRNA) and the knobs of 23 nm could be related to informofers or hnRNA particles. Up to now, the visualization of transcriptional units for higher plant tissues have never been reported.
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Claims 11
Claim · model-written summary
Extranucleolar chromatin spread readily, while nucleolar chromatin often remained aggregated.
- Outcome
- the extranucleolar chromatin was easily spread but the nucleolar chromatin often remained aggregatede0
Zea maysOrganisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Zea mays”
e0“the extranucleolar chromatin was easily spread but the nucleolar chromatin often remained aggregated”
Claim · model-written summary
Nontranscribed chromatin formed long DNP fibrils with a nucleosomal beads-on-a-string appearance.
- Outcome
- long deoxyribonucleoprotein (DNP) fibrils with the typical "beads-on-a-string" appearance of nucleosomal arrangement.e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Zea mays”
e0“The nontranscribed chromatin regions consisted of long deoxyribonucleoprotein (DNP) fibrils with the typical "beads-on-a-string" appearance of nucleosomal arrangement.”
Claim · model-written summary
Increasing EDTA in the spreading medium revealed linear nucleosomes and 20 nm and 40-50 nm DNP granules on one fibril.
- Outcome
- linear arrangement of nucleosomes, 20 nm and 40-50 nm DNP granules were observed on the same DNP fibrile0
- Qualifier
- When the EDTA concentration of the spreading medium was increasede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Zea mays”
e0“When the EDTA concentration of the spreading medium was increased, linear arrangement of nucleosomes, 20 nm and 40-50 nm DNP granules were observed on the same DNP fibril.”
Claim · model-written summary
Supranucleosomal granules were closely packed without apparent order.
- Outcome
- closely packed without any apparent ordere0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Zea mays”
e0“The supranucleosomal granules were also closely packed without any apparent order.”
Claim · model-written summary
Numerous knobby non-nucleolar RNP fibrils were laterally bound to DNP fibrils regardless of EDTA concentration.
- Outcome
- numerous non-nucleolar ribonucleoprotein (RNP) fibrils with a knobby structure were seen laterally bound to DNP fibrilse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Zea mays”
e0“Independently of the EDTA concentration, numerous non-nucleolar ribonucleoprotein (RNP) fibrils with a knobby structure were seen laterally bound to DNP fibrils.”
Claim · model-written summary
RNP transcripts were highly folded into bunch-of-grapes configurations.
- Outcome
- highly folded and appeared in "bunch-of-grapes" configurationse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Zea mays”
e0“These knobby RNP fibrils (transcripts) were highly folded and appeared in "bunch-of-grapes" configurations.”
Claim · model-written summary
Each RNP knob measured 23 nm in diameter.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Zea mays”
e0“Each RNP knob measured 23 nm in diameter”
Claim · model-written summary
The longest RNP fibrils were estimated to reach 1.5 micron.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Zea mays”
e0“the longest of these RNP fibrils were estimated to reach 1.5 micron”
Claim · model-written summary
RNP fibrils were often solitary and never exceeded 8 per 10 micron of the DNP axis.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Zea mays”
e0“The RNP fibrils were often solitary and never exceeded 8 per 10 micron of the DNP axis.”
Claim · model-written summary
Transcript distribution, morphology and size distinguished them from rarely seen nucleolar Christmas-tree figures.
- Outcome
- distinguished them from the nucleolar "Christmas-tree"-like figures, which were rarely observede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Zea mays”
e0“Distribution, morphology, and size of these transcripts distinguished them from the nucleolar "Christmas-tree"-like figures, which were rarely observed with our material.”
Claim · model-written summary
The authors suggest that non-nucleolar transcriptional units may code for hnRNA and 23 nm knobs may represent informofers or hnRNA particles.
- Gene
- genes coding for the heterodisperse nuclear RNA (hnRNA)e0
- Outcome
- non-nucleolar transcriptional unitse0
- Qualifier
- may corresponde0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Zea mays”
e0“These non-nucleolar transcriptional units may correspond to genes coding for the heterodisperse nuclear RNA (hnRNA) and the knobs of 23 nm could be related to informofers or hnRNA particles.”