{'fraction_non_alphanumeric': 0.034403669724770644, 'fraction_numerical': 0.0061162079510703364, 'mean_word_length': 5.233333333333333, '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}}
Structure and developmentally regulated expression of a Strongylocentrotus purpuratus collagen gene.

We have isolated and partially characterized an ca. 20-kilobase-pair Strongylocentrotus purpuratus genomic clone, using a mouse alpha 1 (type IV) collagen cDNA probe. A 1-kilobase-pair HindIII fragment of the clone hybridizes strongly to the probe; this has been subcloned and sequenced. It contains 212 base pairs of sequence coding for (Gly-Xaa-Yaa)n (where Xaa and Yaa are different unspecified amino acids), characteristic of all known collagen genes. There is a single point of discontinuity within the repeating pattern in this exon, similar to the genomic structure of mouse type IV collagen. The (Gly-Xaa-Yaa)n-encoding element is flanked by consensus splicing sequences, and the intervening sequences on either side of it have multiple in-phase termination codons. Electron microscopy of R loops between the phage lambda recombinant clone and poly(A)+ RNA reveals multiple short exons, a feature also seen in vertebrate collagen genes. The (Gly-Xaa-Yaa)n protein-encoding sequence hybridizes to a developmentally regulated 9-kilobase mRNA; the message appears during the morula stage, rises sharply in abundance at the blastula stage, and decreases in proportion to total RNA later in development.