All Phenotypes Gfi1<tm3(Gfib1)Tmo> MGI Mouse

hematopoietic system phenotype ( J:116870 )

N

• unlike Gfi1^tm1Tmo mutant mice, these homozygotes show normal pre-T-cell development, are not neutropenic, and exhibit no significant expansion of monocytoid cells and a normal distribution of granulocytes (Mac-1^hi/Gr-1^hi) and monocytes (Mac-1⁺) in peripheral blood

• no shortened lifespan, granuloma formation or an inherent predisposition to infections is observed

decreased granulocyte number ( J:116870 )

• in bone marrow, homozygotes exhibit slightly reduced frequencies of granulocytes; however, this phenotype is closer to the wild-type configuration than that observed in Gfi1^tm1Tmo homozygotes

• the proportion of mature granulocytes is slightly reduced in peripheral blood, while a left shift towards more immature granulocytic precursors is noted in bone marrow

abnormal monocyte morphology ( J:116870 )

• in bone marrow, homozygotes exhibit a mild accumulation of cells with the immunophenotype of immature myeloid cells or monocytes (Mac-1^lo, Gr-1^lo); however, this phenotype is closer to the wild-type configuration than that observed in Gfi1^tm1Tmo homozygotes

• a few 'atypical monocytes', typical for Gfi1^tm1Tmo homozygotes, are also observed in blood and bone marrow

abnormal cochlear inner hair cell morphology ( J:116870 )

• at P0, homozygotes exhibit a single row of morphologically immature IHCs, similar to Gfi1^tm1Tmo homozygotes

abnormal cochlear outer hair cell morphology ( J:116870 )

• at P0, OHCs appear smaller and disorganized, though less severely affected relative to Gfi1^tm1Tmo homozygotes

absent outer hair cell stereocilia ( J:116870 )

cochlear outer hair cell degeneration ( J:116870 )

• at P0, homozygotes display progressive OHC degeneration, albeit at an apparently slower rate relative to to Gfi1^tm1Tmo homozygotes

increased or absent threshold for auditory brainstem response ( J:116870 )

• at 3-3.5 months of age, homozygotes display increased ABR thresholds that are >100 dB at 8 kHz and >90 dB at 16 and 32 kHz, similar to Gfi1^tm1Tmo homozygotes

deafness ( J:116870 )

• similar to Gfi1^tm1Tmo mutant mice, homozygotes are deaf, suggesting that Gfi1b can replace Gfi1 functionally in haematopoiesis but not in inner ear hair cell development

absent pinna reflex ( J:116870 )

• homozygotes fail to show a Preyer reflex

head bobbing ( J:116870 )