Figure 1.
a, ORF map of ML4 cDNA. Short vertical bars denote possible translation start sites; long bars denote stop codons. The ML4 coding region is gray shaded. The 2,272-bp ML4 transcript contains an ORF of 1,635 bp encoding a protein of 545 amino acids. A 2,037-bp alternative spliced form, missing a 235-bp region that is denoted by the thick bar, also is shown. Since te size of the spliced region is not an exact multiple of 3, this alternative ML4 transcript presents a longer ORF (1,740 bp, encoding a 580-amino-acid protein), with the first Met located at nucleotide position 81. The proteins encoded by the two forms differ in their NH2 portions, whereas they are identical for the last 345 residues, because of the usage of the same reading frame in the two transcripts (the region denoted by the double-arrowheaded line) downstream of the splicing event. b, Northern blot analysis of the ML4 gene. A cDNA probe spanning the entire coding sequence of ML4 was hybridized to commercially available northern blot containing 2 μg of poly(A)+ RNA from various human adult tissues. A band of ∼2.2 kb, consistent with the size of the cDNA contig, is detected in all tissues tested, with the exception of colon and thymus. Hybridization to a human β-actin cDNA revealed almost equal amounts of poly(A)+ RNA in each lane.