Expression of betaB(2)-crystallin mRNA and protein in retina, brain, and testis

Invest Ophthalmol Vis Sci. 2000 Sep;41(10):3056-60.


Purpose: To evaluate the expression of betaB(2)-crystallin mRNA and protein in rat, bovine, and human nonlens and nonocular tissues.

Methods: betaB(2)-crystallin mRNA levels were detected by RT-PCR. betaB(2)-crystallin protein was purified from rat and bovine tissues by FPLC chromatography. FPLC fractions were analyzed by immunoblotting. The identity of betaB(2)-crystallin protein, isolated from the retina, was confirmed by protein microsequencing.

Results: betaB(2)-crystallin transcript was detected in rat brain, rat testis, and human retina by RT-PCR. betaB(2)-crystallin transcript was not found in rat lung, heart, ovary, spleen, thymus, kidney, and liver or in human brain and testis. betaB(2)-crystallin protein was partially purified from and its identity confirmed in rat brain, rat testis, and bovine retina. The bovine retinal protein was further confirmed to be authentic betaB(2)-crystallin by protein microsequencing.

Conclusions: These results establish that betaB(2)-crystallin mRNA and protein are expressed in tissues outside of the lens and outside of the eye including retina, brain, and testis. Extralenticular and extraocular expression of betaB(2)-crystallin, coupled with its participation in phosphorylation pathways, suggests that it has nonrefractive functions in these tissues.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Brain / metabolism*
  • Cattle
  • Chromatography, High Pressure Liquid
  • Crystallins / biosynthesis
  • Crystallins / genetics*
  • DNA Primers / chemistry
  • Gene Expression
  • Humans
  • Immunoblotting
  • Male
  • RNA, Messenger / biosynthesis*
  • Rats
  • Retina / metabolism*
  • Reverse Transcriptase Polymerase Chain Reaction
  • Testis / metabolism*
  • beta-Crystallin B Chain* / analogs & derivatives*


  • Crystallins
  • DNA Primers
  • RNA, Messenger
  • beta-Crystallin B Chain
  • beta-crystallin B2