rib¹/rib^35.14 and rib¹/rib^55.25 transheterozygous embryos display a significant increase in defects in the fusion together and compaction of primordial germ cells and somatic gonadal precursor cells, as compared to controls.

The developing salivary glands in rib¹ mutant animals fail to turn and migrate properly. In addition, the dorsal trunks of the trachea exhibit only partial extension at stage 14, but relatively normal extension of dorsal and visceral branches occurs. These defects are also observed in rib¹/rib^P7 animals.

rib¹/rib^P7 mutant animals have normal salivary gland epithelial cell architecture, but exhibit short lumena with distally tilted apical-basal cell axes. There are reduced numbers of apical vesicles and increased microvillar structure.

Salivary gland cells form a wider and shorter tube than normal in mutant embryos, with the distal tip at the "turning point" (the point where the cells turn to reorient their movement posteriorly in wild-type embryos).

The specification of tracheal primordia appears to be normal in these mutants. There are also no overt differences in the shape and size of tracheal placodes and the invagination of tracheal cells is initiated with similar timing and positioning as wild-type. Differences are first apparent during stage 12, when outgrowth of branches is either absent or delayed. By stage tracheae are clearly defective in a subset of branches. In most segments the dorsal trunk (DT) is completely absent, and cells are clustered at the position within the tracheal sac from which the DT cells normally migrate. In a few metameres, the cluster of DT cells in the trachea have fewer cells, and the corresponding dorsal branch contain additional cells. The lateral trunk (LT) and ganglionic branch (GB) are also defective, both branches are stunted and often the LT is completely absent. Unlike the DTs, which only rarely migrate, migrating GBs are frequently observed at later stages, although they are often misrouted. Migration of the other two primary branches the dorsal branch and the visceral branch are generally unaffected, except for occasional extra DB cells. The lumina of all branches of trachea appear more dilated than in wild-type. In rib²/rib² or rib²/rib¹ larvae, of those with scorable cuticles, small anterior dorsal holes and puckering of the dorsal epidermis occur in 36% of mutants and large dorsal holes occur in 64% of mutants. Denticle belt phenotypes are also seen. The lateral extent of rib²/rib² denticle belts is narrowed to 27% that of wild-type, rib²/rib¹ belts reduced to 46%. A loss of denticle diversity is also seen in the embryos. The secretory gland primordia in rib¹ mutants are indistinguishable from those in wild-type embryos, and internal invagination proceeds normally. However secretory cells do not migrate past the point at which wild-type cells turn and migrate posteriorly - they never reach their final destination. At late stages, the lumina of the salivary glands are greatly enlarged compared to wild-type glands. The salivary duct also fails to undergo proper morphogenesis in mutants. In late stage mutant embryos, either no tubes or rudimentary individual tubes connect to the secretory glands; these semi-tubular structures do not elongate and never elaborate into a normal duct.

Homozygous and rib¹/Df(2R)rib-ex12 embryos show defects in tracheal branch outgrowth. A small number of rib^P16/rib¹ escapers survive to adulthood.

The salivary gland of mutant embryos is short and wide with an open lumen. Malpighian tubules are much shorter and wider than wild type. Embryos show a failure of dorsal closure and lack midgut constrictions. Embryos lack cuticular hairs and denticles almost completely. The remaining hairs are either much longer than normal or are abnormally curved.

Most epidermal cells remain polygonal during dorsal closure in homozygous embryos, in contrast to wild-type where the cells elongate dorsoventrally. Dorsal margin epidermal cells are conspicuously round in homozygous embryos and are larger than the more ventral epidermal cells. Some cells in the dorsolateral epidermis elongate slightly, but only a few cells elongate as much as wild-type embryos. The shape of the salivary glands and hindgut is abnormal, and the cells of both these organs are less columnar than in wild-type; salivary gland cells are approximately the same width as wild-type, but shorter than wild-type, and hindgut cells are both wider and shorter than wild-type. The salivary gland cells lack the wedge shape characteristic of wild-type salivary gland cells.

Malpighian tubules have a greater circumference than normal at their proximal end in homozygous embryos, giving them a gourd-like shape. The lumen of the tubules is greatly enlarged compared to wild-type. The epidermis never closes dorsally, the central nervous system fails to retract and the midgut does not constrict. Little if any head involution occurs. The secretory portion of the salivary gland is wider and has a much larger lumen than normal. In most embryos the salivary gland ducts do not move to the ventral midline and fuse, but remain open to the outside of the embryo. The hindgut is shorter and wider than normal, forming a bulb instead of a tube. Hindgut cells are less columnar than wild-type cells and the number of cells in the circumference of the hindgut is larger than normal. Tracheal branches usually fail to grow out, and those that do grow never contact branches from neighbouring segments. The tracheae that form have a larger diameter than normal. The peripheral nervous system (PNS) is mildly disorganised; the clusters of sense organs are indistinct and compacted dorsoventrally. The two ventral clusters and lateral cluster of each hemisegment are often combined into a single large cluster, and the dorsal clusters are compacted into a tight bunch. The five chordotonal organs of the lateral cluster are positioned randomly rather than in a straight row. The salivary gland and tracheal phenotypes are more severe in rib¹/Df(2R)P34 hemizygous embryos.

narrow; fusion of adjacent denticle bands in ventral midline; dorsal closure defective. embryonic lethal lateral extents of belts

rib¹, zip^mhc-c3.9 has viable phenotype

rib¹, zip^mhc-c3.12 has viable phenotype

rib¹, zip^mhc-c6.1 has viable phenotype

rib¹, zip^mhc-c14 has viable phenotype

rib¹, zip^IIX62 has viable phenotype

rib¹, zip^mhc-c1.3 has viable phenotype

rib¹, zip^mhc-c1.6 has viable phenotype

rib¹, zip² has viable phenotype

rib¹, zip^mhc-c2.1 has viable phenotype

rib^P7/rib¹ has presumptive embryonic salivary gland phenotype, suppressible | partially by crb^intra.UAS/Scer\GAL4^btl.PS

rib^P7/rib¹ has tracheal dorsal trunk primordium phenotype, suppressible | partially by Scer\GAL4^btl.PS/Moe^{T559A.UAS.Tag:MYC}

rib¹ has embryonic/larval salivary gland | embryonic stage phenotype, suppressible by zip^mhc-c1.3

rib¹ has Malpighian tubule phenotype, suppressible by zip^mhc-c1.3

rib¹ has embryonic/larval salivary gland | embryonic stage phenotype, suppressible by zip²

rib¹ has Malpighian tubule phenotype, suppressible by zip²

rib¹ has denticle phenotype, suppressible by zip²

rib¹ has larval dorsal hair phenotype, suppressible by zip²

rib^P7/rib¹ has tracheal dorsal trunk primordium phenotype, non-suppressible by crb^intra.UAS/Scer\GAL4^btl.PS

rib^P7/rib¹ has presumptive embryonic salivary gland phenotype, non-suppressible by Scer\GAL4^fkh.PH/crb^UAS.cWa

rib^P7/rib¹ has tracheal dorsal trunk primordium phenotype, non-suppressible by crb^UAS.cWa/Scer\GAL4^btl.PS

rib^P7/rib¹ has presumptive embryonic salivary gland phenotype, non-suppressible by Scer\GAL4^fkh.PH/Moe^{T559A.UAS.Tag:MYC}

rib¹ has embryonic/larval salivary gland | embryonic stage phenotype, non-suppressible by zip^mhc-c3.12

rib¹ has embryonic/larval salivary gland | embryonic stage phenotype, non-suppressible by zip^mhc-c6.1

rib¹ has embryo | dorsal closure stage phenotype, non-suppressible by zip²

rib¹ has embryonic midgut constriction phenotype, non-suppressible by zip²

rib¹ has Malpighian tubule phenotype, non-suppressible by zip^mhc-c2.1

rib¹ has Malpighian tubule phenotype, non-suppressible by zip^mhc-c3.12

rib¹ has Malpighian tubule phenotype, non-suppressible by zip^mhc-c6.1

rib¹ has embryonic/larval salivary gland | embryonic stage phenotype, non-suppressible by zip^mhc-c2.1

rib¹, tkv⁴ has tracheal section phenotype

raw¹, rib¹ has presumptive embryonic/larval peripheral nervous system phenotype

raw¹, rib¹ has larval tracheal system phenotype

raw¹, rib¹ has embryonic/larval salivary gland | embryonic stage phenotype