Q.93 In the context of cell differentiation, lateral inhibition is referred 1o as the
(A) formation of two distinct cell types within a uniform field,
(B) inhibilion of formation of a distinct cell type next to an existing cell type.
(C) inhibition of stem cells towards self-renewal.
(D) inhibition of erythopoesis in the lateral plate mesoderm.

Lateral Inhibition in Cell Differentiation: MCQ Answer and Explanation

Lateral inhibition is a key process in developmental biology where cells differentiate into distinct types through Notch signaling. It ensures patterned development from uniform fields, crucial for neural and sensory tissues.

Correct Answer

(B) inhibition of formation of a distinct cell type next to an existing cell type

Lateral inhibition, via Notch-Delta signaling, occurs when one cell adopts a fate (e.g., neuron) and signals neighbors to adopt a different fate (e.g., support cell), preventing identical fates side-by-side. This refines a uniform field into a salt-and-pepper pattern of distinct cell types, as seen in Drosophila neurogenesis. It amplifies initial biases, ensuring spaced differentiation without overproduction.

Option Explanations

(A) Formation of Two Distinct Cell Types Within a Uniform Field

This describes the outcome of lateral inhibition but not the mechanism itself. Lateral inhibition actively creates such patterns from equivalent cells, yet the option lacks the inhibitory neighbor interaction central to the process.

(B) Inhibition of Formation of a Distinct Cell Type Next to an Existing Cell Type (Correct)

A committed cell expresses Delta ligands, activating Notch in adjacent cells to suppress the same fate via Hes/Enhancer-of-split genes. This “winner-takes-all” dynamic stabilizes diversity, as in proneural clusters where one neural precursor inhibits siblings.

(C) Inhibition of Stem Cells Towards Self-Renewal

Stem cell self-renewal inhibition relates more to asymmetric division or quiescence signals, not lateral inhibition. Lateral inhibition acts among equivalent progenitors, not specifically targeting stem cell renewal pathways like Wnt or BMP.​

(D) Inhibition of Erythropoiesis in the Lateral Plate Mesoderm

Erythropoiesis (RBC formation) occurs in blood islands of lateral plate mesoderm, regulated by BMP/Smad and Gata factors, not Notch-mediated lateral inhibition. This is unrelated to the standard definition in ectodermal/neural contexts.​

This clarifies lateral inhibition for exams, emphasizing its role in patterning via neighbor suppression.