Table 1. New branch formation by budding... | Rockefeller University Press

Table 1.

New branch formation by budding versus clefting

Cellular mechanisms	Budding	Clefting
Initiation of new branches	Protrusion of a group of cells outward from an epithelium to generate a new branch tip (in blood vessels, Drosophila trachea, mammary gland, lung, kidney,^{^a} and pancreas^{^b})	Separation of cells in a preexisting branch tip to generate two or more new branch tips (in salivary gland,^{^c} lung, kidney, and pancreas^{^b})
Collective cell migration
Invasive	Drosophila trachea	—
	Blood vessels
Noninvasive	Mammary gland	—
	Lung (?)
	Kidney (?)
Patterned cell proliferation
Regionalized proliferation	Lung	—
	Kidney
Oriented cell division	—	Lung
		Kidney (?)
Actomyosin contractility	Not required in blood vessels and lung	Salivary gland, kidney,
	Required in mammary gland (?) and pancreas^{^b}	lung, pancreas^{^b}
Differential cell motilities	Mammary gland	Salivary gland
	Pancreas^{^b}	Pancreas^{^b}
Physical constraint
By basement membrane	—	Salivary gland
By smooth muscle cells	—	Lung

Cellular mechanisms	Budding	Clefting
Initiation of new branches	Protrusion of a group of cells outward from an epithelium to generate a new branch tip (in blood vessels, Drosophila trachea, mammary gland, lung, kidney,^{^a} and pancreas^{^b})	Separation of cells in a preexisting branch tip to generate two or more new branch tips (in salivary gland,^{^c} lung, kidney, and pancreas^{^b})
Collective cell migration
Invasive	Drosophila trachea	—
	Blood vessels
Noninvasive	Mammary gland	—
	Lung (?)
	Kidney (?)
Patterned cell proliferation
Regionalized proliferation	Lung	—
	Kidney
Oriented cell division	—	Lung
		Kidney (?)
Actomyosin contractility	Not required in blood vessels and lung	Salivary gland, kidney,
	Required in mammary gland (?) and pancreas^{^b}	lung, pancreas^{^b}
Differential cell motilities	Mammary gland	Salivary gland
	Pancreas^{^b}	Pancreas^{^b}
Physical constraint
By basement membrane	—	Salivary gland
By smooth muscle cells	—	Lung

—, not yet described or established.

Ureteric bud in kidney.

Mechanisms of pancreas branching may be complex, including a unique process involving the formation of microlumens.

Submandibular salivary gland.