{'fraction_non_alphanumeric': 0.038817005545286505, 'fraction_numerical': 0.022181146025878003, 'mean_word_length': 5.548387096774194, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Mouse kidney nonpolysomal messenger ribonucleic acid: metabolism, coding function, and translational activity.

To elucidate the distribution and function of mRNA in mouse kidney cytoplasm, we compared mRNA isolated from polysomal (greater than 80S) and native postpolysomal (20--80S) ribonucleoproteins with respect to synthesis and lifetime, sequence content, and translational activity. The 20--25% of cytoplasmic mRNA recovered from postpolysomal ribonucleoprotein is similar to polysomal mRNA in size (20--22S), in apparent half-life (11--13 h), in major products of cell-free translation, and in nucleotide complexity (approximately 4 x 10(7) nucleotides). The labeling kinetics of polysomal and postpolysomal mRNA suggest these mRNA populations are in equilibrium. [3H]cDNAs transcribed from polysomal and from postpolysomal poly(A)-containing mRNAs react with template mRNA and with the heterologous mRNA at the same rate (Cot1/2 approximately 6.3 mol.s/L) and to the same extent (95%). Therefore, these mRNAs are equally diverse and homologous and occur at similar relative frequencies. Postpolysomal mRNA directs cell-free protein synthesis at only approximately 30% of the rate of polysomal mRNA and to only 30% of the extent of mRNA from polysomes. Postpolysomal mRNA is approximately 3-fold less sensitive than polysomal mRNA to inhibition of translation by m7GMP, suggesting postpolysomal mRNA contains a greater fraction of molecules deficient in 5'-terminal caps. Postpolysomal mRNA may derive from renal mRNAs that initiate translation inefficiently and thus accumulate as postpolysomal ribonucleoproteins.