David B. Malcolm

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The morphology of the lateral loops of newt oocyte chromosomes results from the state of aggregation of the ribonucleoprotein which constitutes the loop matrix. This ribonucleoprotein consists of the RNA products of transcription in association with various non-basic proteins. During vitellogenesis there is marked variation in the size and appearance of the(More)
Nuclear RNP from Triturus oocytes is organized as strings of beads which can be converted into 20-nm-diameter monoparticles with mild RNase treatment or into 5-nm-thick linear fibrils with low salt treatment. The protein component comprises a heterogeneous size-range of polypeptides which differ from the polypeptides of the other nucleoproteins of oocytes.(More)
Immunofluorescent reactions specific for distinct chromosomal structures are obtained by using antiserum to oocyte proteins. Antisera diluted more than 1000-fold are used to localize proteins associated with RNA transcripts in unfixed lampbrush chromosomes of Triturus cristatus carnifex. Of the several protein components of nuclear RNP, at least some are(More)
The meiotic lampbrush chromosomes of amphibian oocytes display readily distinguishable regions of transcription (lateral loops) which extend from axial condensates of chromatin (chromomeres). The chromomeres contain most of the chromosomal ENA which, along with histone, is tightly compacted as regular arrays of DNP. Many RNA transcripts are generated on the(More)
The lampbrush chromosomes of amphibian oocytes are highly active in RNA transcription. The extent of transcription and features of the transcriptional product have been studied both cytologically and by molecular hybridization. Each lampbrush loop is considered to be a unit of transcription which generates many primary transcript molecules. InTriturus the(More)
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