cramped

DEVELOPMENTAL BIOLOGY

Embryonic and Larval stages

Nuclear staining persists at similar levels during both cellularization and gastrulation. There is significant staining in the pole cells. Later in development, strong staining is visible in the central nervous system and the gonads (Yamamoto, 1997).

crm gene product is localized to the nucleus during embryogenesis. This nuclear localization appears to be restricted to S-phase nuclei, since Crm immunostaining disappears at mitosis. This cell-cycle-dependent staining pattern is identical to that of proliferating cell nuclear antigen (PCNA). Crm and PCNA proteins are co-localized in salivary gland polytene nuclei (Yamamoto, 1997).

Effects of mutation or deletion

Typically, hemizygous mutant males or homozygous females die late in development, with lethality periods ranging from third instar to late pupal stages. Homozygous female escapers are sterile and have rudimentary ovaries with no oocytes beyond stage 7. crm mutants exhibit typical Pc-G mutant phenotypes, reminiscent of ectopic homeotic gene expression, with additional sex comb teeth found on mesothoracic and metathoracic legs, and proximodistal transformations of the tarsal segments. Mutants show a typical altered morphology of the antennae: swollen antennae, short aristae with fewer branches than in wild type. Genetic interactions are found with other Polycomb-Group members. Males with crm and Pc mutations die as pharate adults, with second and third legs completely transformed towards the first. Ectopic sex comb teeth are found on the second tarsal segment of all flies (Yamamoto, 1997).

There is a genetic interaction between crm and mus209, the Drosophila gene encoding PCNA (Yamamoto, 1997).

Uhlmann, F., et al. (1997). Deletion analysis of the large subunit p140 in human replication factor C reveals regions required for complex formation and replication activities. J. Biol. Chem. 272(15): 10058-10064.

Yamamoto, Y., et al. (1997). The cramped gene of Drosophila is a member of the Polycomb-group, and interacts with mus209, the gene encoding Proliferating Cell Nuclear Antigen. Development 124(17): 3385-3394.

date revised: 20 October 97  

Home page: The Interactive Fly © 1997 Thomas B. Brody, Ph.D.

The Interactive Fly resides on the
Society for Developmental Biology's Web server.