sec620 is the product of an imprecise excision of P{EP}EP2021 that deletes the DNA encoding the 242 carboxy-terminal amino acids of the sec6 protein.
cytoplasmic vesicle & eye photoreceptor cell | somatic clone, with Scer\GAL4ey.PH, Sec6UASp.cBa
endoplasmic reticulum & eye photoreceptor cell | somatic clone, with Scer\GAL4ey.PH, Sec6UASp.cBa
microvillus & eye photoreceptor cell | somatic clone, with Scer\GAL4ey.PH, Sec6UASp.cBa
sec620 mutant animals fail to grow as larvae and die at approximately 72 hours after egg laying.
sec620 hemizygous and homozygous animals show identical phenotypes.
Follicles containing a sec620 germ-line clone show no apparent defects during early stages. However, by stage 6-7, plasma membrane is undetectable between germ-line cells, ring canals collapse to a single clump within the germline cyst, and nuclei show an irregular arrangement. sec620 mutant follicles are not observed past stage 7, suggesting that they degenerate.
Eye development is almost abolished when sec620 mutant clones are induced in the eye and wild type sister clones are ablated.
Eyes that are mutant for sec620 (made by inducing sec620 mutant clones and genetically ablating wild type sister clones) and which also express sec6Scer\UAS.P\T.cBa under the control of Scer\GAL4ey.PH are referred to as 'sec6(pr)' (for 'partial rescue') eyes. sec6(pr) mutant eyes develop to near normal size in the adult but are slightly rough and interommatidial bristles are virtually absent. Defects in the differentiation of the cornea and the pigment cells are apparent that are more severe in the anterior half of the eye. At 55% pupal development, gross morphological defects are not apparent in sec6(pr) mutant photoreceptors, although there are some defects in the organization of microvilli and a conspicuous increase in cytoplasmic vesicles compared to wild type. At 90% pupal development, sec6(pr) mutant photoreceptors appear swollen and have smaller and flattened rhabdomeres compared to wild type, and their cytoplasm is filled with vesicles of 100-300 nm diameter that are only rarely seen in wild type; the proximal-distal length of sec6(pr) rhabdomeres is significantly reduced compared to wild type, and the sec6(pr) retina as a whole reaches only approximately half the depth of a wild type retina; some sec6(pr) photoreceptor cells also have an enlarged endoplasmic reticulum. In one-day-old adult flies, the photoreceptors and other retinal cells of sec6(pr) eyes show widespread signs of degeneration; the rhabdomeres of photoreceptors are either strongly reduced in size or are missing.
Sec620 is rescued by Sec6UAS.C-YFP/Scer\GAL45-40
Sec620 is partially rescued by Sec6UASp.cBa/Scer\GAL4ey.PH
Expression of Sec6Scer\UAS.T:Avic\GFP-CYFP under the control of Scer\GAL45-40 in Sec620/Sec620 class IV dendritic arborizing neurons in larval somatic clones fully rescues the dendritic growth defects displayed by Sec620/Sec620 neurons (reduction in both total dendrite length and number of terminal dendrites).
Expression of sec6Scer\UAS.P\T.cBa under the control of Scer\GAL4ey.PH substantially rescues the 'small eye' phenotype seen when sec620 mutant clones are induced in the eye and wild type sister clones are ablated.
Isolated as an imprecise excision of P{EP}EP2021.