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We have previously reported on the identification of a cDNA clone encoding a novel human growth factor, named "CRIPTO," that is abundantly expressed in undifferentiated human NTERA-2 clone D1 (NT2/D1) and mouse (F9) teratocarcinoma cells. We now report the organization and nucleotide sequence of two related genomic sequences. One (CR-1) corresponds to the structural gene encoding the human CRIPTO protein expressed in the undifferentiated human teratocarcinoma cells, and the other (CR-3) corresponds to a complete copy of the mRNA containing seven base substitutions in the coding region representing both silent and replacement substitutions. The 440 bp 5' to the CAP site of CR-1 are preserved in CR-3. CR-1 maps to chromosome 3, and CR-3 maps to Xq21-q22. Southern blot analysis reveals that multiple CRIPTO-related DNA sequences are present in the human as well as in the mouse genome.

We have previously reported on the identification of a cDNA clone encoding a novel human growth factor, named "CRIPTO," that is abundantly expressed in undifferentiated human NTERA-2 clone D1 (NT2/D1) and mouse (F9) teratocarcinoma cells. We now report the organization and nucleotide sequence of two related genomic sequences. One (CR-1) corresponds to the structural gene encoding the human CRIPTO protein expressed in the undifferentiated human teratocarcinoma cells, and the other (CR-3) corresponds to a complete copy of the mRNA containing seven base substitutions in the coding region representing both silent and replacement substitutions. The 440 bp 5' to the CAP site of CR-1 are preserved in CR-3. CR-1 maps to chromosome 3, and CR-3 maps to Xq21-q22. Southern blot analysis reveals that multiple CRIPTO-related DNA sequences are present in the human as well as in the mouse genome.

This study isolated cDNA clones from egg-chamber and adult female Drosophila cDNA libraries using as probe a DNA fragment from a 200-kb “chromosome walk” in region 32E of the second chromosome of D. melanogaster. The present authors believe that these clones correspond to a new vitelline membrane protein (VMP) gene because (1) cDNA clones in Northern blots identify a transcript expressed in a tissue- and stage-specific manner: stage 10 egg-chambers; (2) the sequence of cDNAs and of the genomic subclone shows homology with the other VMP genes that have been identified to date; (3) the amino acid composition of the translational product has the high content of proline and alanine characteristic of VMPs. Two aspects emerging from this study are worth stressing: (1) the presence of a hydrophobic domain that is highly conserved in all the VMP genes; and (2) the particularly narrow period of expression of the isolated gene, which could be related to the mechanism of vitelline membrane assembly.

The authors have studied the interaction between the abnormal oocyte mutation and an inversion of the X chromosome, In(1)sc 4, which has a proximal breakpoint in or near the heterochromatic region (ABO) that maternally interacts with the abo product. It has been demonstrated that the presence of X chromosomes carrying this inversion, besides a marked increase in the severity of the maternal effect of the abo mutation, produces a zygotic effect resulting in the lethality of the progeny of stocks homozygous for abo and sc 4. These results indicate that the sc 4 inversion carries an abnormal region indispensable for the development of abo zygotes from sc 4;abo mothers.