E. coli K-12 MG1655

lacZ

beta-galactosidase

Locus tag: b0344
Reference assembly: GCF_000005845.2
Sequence: NC_000913.3
Gene interval: 363,231–366,305 · - strand
Coordinate system: 1-based, inclusive

Published evidence

Observed outcome · Same reference background

lacZ deletion did not slow growth on galactose in this comparison

Table 5 reports the same galactose doubling time for the study wild type and its lacZ-deletion derivative. A lacY amber mutant grew more slowly.

Study strain: MG1655-derived NCM3387 compared with NCM3384

Conditions: Defined medium with galactose and IPTG; this is not a lactose-only growth result.

Physiological Studies of Escherichia coli Strain MG1655: Growth Defects and Apparent Cross-Regulation of Gene Expression

Gene function · Same reference background

Lactose breakdown

lacZ encodes beta-galactosidase. Its enzyme activity supports lactose breakdown and chromogenic beta-galactosidase assays.

Study strain: K-12 MG1655

Conditions: A color assay requires a suitable substrate; expression and substrate access also matter.

NCBI Gene: lacZ (b0344)

Review the experimental evidence

Compare the experimental backgrounds and read the supporting sources.

Does a lacZ deletion prevent E. coli growth, or does the carbon source change the conclusion? — MG1655-derived NCM3384 and NCM3387
Does lower ONPG color mean less LacZ enzyme? — MG1655 ΔlacI versus MG1655 ΔlacI ΔlacY

Nearby genes

cynX · b0341 — cyanate transporter
lacA · b0342 — galactoside O-acetyltransferase
lacY · b0343 — lactose permease
lacZ · b0344 — beta-galactosidase
lacI · b0345 — DNA-binding transcriptional repressor LacI
mhpR · b0346 — DNA-binding transcriptional activator MhpR
mhpA · b0347 — 3-(3-hydroxyphenyl)propanoate hydroxylase

Reference and sequence

NCBI reference annotation · Reference gene interval · Download gene DNA (FASTA)

Gene-level evidence does not identify a validated nucleotide edit. Evaluate the study’s strain and conditions before applying an observation to another background.